how to determine level of jpeg compression

[Paddy]

I had a little photoshoot today of my two daughters. I agreed to purchase the CD of the shoot providing the images were uncompressed as I want to get some of the images put onto canvas.

There must be some compression as the files are ~3MB in JPEG format. Before I phone tomorrow to get my money back is there anyway that I can determine the level of JPEG compression? I can supply the file if required (but I cant upload it here due to filesize)...

[Paddy]

I googled my query and found a program called JPEGsnoop. Here are the results:

JPEGsnoop 1.1.3 by Calvin Hass
  www.impulseadventure.com
  ------------------------

  Filename: [C:\Users\Patrick\Desktop\1.jpg]
  Filesize: [3608463] Bytes

Start Offset: 0x00000000
*** Marker: SOI ***
  OFFSET: 0x00000002
 
*** Marker: APP0 ***
  OFFSET: 0x00000004
  length     = 16
  identifier = [JFIF]
  version    = [1.2]
  density    = 314 x 314 DPI (dots per inch)
  thumbnail  = 0 x 0
 
*** Marker: APP1 ***
  OFFSET: 0x00000016
  length          = 6520
  Identifier      = [Exif]
  Identifier TIFF = x[4D 4D 00 2A 00 00 00 08 ]
  Endian          = Motorola (big)
  TAG Mark x002A  = x[002A]

  EXIF IFD0 @ Absolute x[00000026]
    Dir Length = x[000C]
    [ImageDescription                    ] = OLYMPUS DIGITAL CAMERA         
    [Make                                ] = OLYMPUS CORPORATION    
    [Model                               ] = E-1             
    [Orientation                         ] = 1
    [XResolution                         ] = 314/1
    [YResolution                         ] = 314/1
    [ResolutionUnit                      ] = 2
    [Software                            ] = Microsoft Windows Photo Gallery 6.0.6000.16386
    [DateTime                            ] = 2007:12:06 15:40:42
    [YCbCrPositioning                    ] = 2
    [ExifOffset                          ] = x013C
    [IFD0.xC4A5                          ] = x0000039E
    Offset to Next IFD = [00000492]

  EXIF IFD1 @ Absolute x[000004B0]
    Dir Length = x[0006]
    [Compression                         ] = 6
    [XResolution                         ] = 1/72
    [YResolution                         ] = 1/72
    [ResolutionUnit                      ] = 2
    [JpegIFOffset                        ] = 1264
    [JpegIFByteCount                     ] = 5248
    Offset to Next IFD = [00000000]

  EXIF SubIFD @ Absolute x[0000015A]
    Dir Length = x[001E]
    [ExposureTime                        ] = 1/125
    [FNumber                             ] = 130/10
    [ExposureProgram                     ] = 1
    [ISOSpeedRatings                     ] = 100
    [ExifVersion                         ] = x30323231
    [DateTimeOriginal                    ] = 2007:12:06 14:59:09
    [DateTimeDigitized                   ] = 2007:12:06 14:59:09
    [ComponentConfiguration              ] = x01020300
    [ExposureBiasValue                   ] = 0/10
    [MaxApertureValue                    ] = 925/256
    [MeteringMode                        ] = 5
    [LightSource                         ] = 9
    [Flash                               ] = 0
    [FocalLength                         ] = 31/1
    [UserComment                         ] = x000002FA
    [FlashPixVersion                     ] = x30313030
    [ColorSpace                          ] = 1
    [ExifImageWidth                      ] = 1920
    [ExifImageHeight                     ] = 2560
    [ExifInteroperabilityOffset          ] = 888
    [FileSource                          ] = x03000000
    [CustomRendered                      ] = 0
    [ExposureMode                        ] = 1
    [WhiteBalance                        ] = 1
    [DigitalZoomRatio                    ] = 0/100
    [SceneCaptureType                    ] = 0
    [GainControl                         ] = 0
    [Contrast                            ] = 0
    [Saturation                          ] = 0
    [Sharpness                           ] = 0
 
*** Marker: APP13 ***
  OFFSET: 0x00001990
  length          = 7366
  Identifier      = [Photoshop 3.0]
    8BIM: [0x0404] Name(0)=[] Len=[0x005E]
      IPTC [0x1C02:000] Record Version = [0x0002]
      IPTC [0x1C02:120] Caption-Abstract = [OLYMPUS DIGITAL CAMERA         ]
      IPTC [0x1C02:065] OriginatingProgram = [Microsoft Windows Photo Gallery 6.0.6000.16386]
    8BIM: [0x0425] Name(0)=[] Len=[0x0010]
    8BIM: [0x03ED] Name(0)=[] Len=[0x0010]
    8BIM: [0x0426] Name(0)=[] Len=[0x000E]
    8BIM: [0x040D] Name(0)=[] Len=[0x0004]
    8BIM: [0x0419] Name(0)=[] Len=[0x0004]
    8BIM: [0x03F3] Name(0)=[] Len=[0x0009]
    8BIM: [0x040A] Name(0)=[] Len=[0x0001]
    8BIM: [0x2710] Name(0)=[] Len=[0x000A]
    8BIM: [0x03F5] Name(0)=[] Len=[0x0048]
    8BIM: [0x03F8] Name(0)=[] Len=[0x0070]
    8BIM: [0x0408] Name(0)=[] Len=[0x0010]
    8BIM: [0x041E] Name(0)=[] Len=[0x0004]
    8BIM: [0x041A] Name(0)=[] Len=[0x0349]
    8BIM: [0x0428] Name(0)=[] Len=[0x000C]
    8BIM: [0x0414] Name(0)=[] Len=[0x0004]
    8BIM: [0x040C] Name(0)=[] Len=[0x167F]
    8BIM: [0x0421] Name(0)=[] Len=[0x0079]
    8BIM: [0x0406] Name(0)=[] Len=[0x0007]
  Photoshop Save As Quality        = [12]
  Photoshop Save Format            = [Standard]
 
*** Marker: APP1 ***
  OFFSET: 0x00003658
  length          = 7801
  Identifier      = [http://ns.adobe.com]
    Not EXIF. Skipping remainder.
 
*** Marker: APP2 ***
  OFFSET: 0x000054D3
  length          = 3160
  Identifier      = [ICC_PROFILE]
    Not Flashpix. Skipping remainder.
 
*** Marker: APP14 ***
  OFFSET: 0x0000612D
  length     = 14
 
*** Marker: DQT ***
  Define a Quantization Table.
  OFFSET: 0x0000613D
  Table length = 67
  ----
  Precision=8 bits
  Destination ID=0 (Luminance)
    DQT, Row #0:   1   1   1   1   1   1   1   2 
    DQT, Row #1:   1   1   1   1   1   1   1   2 
    DQT, Row #2:   1   1   1   1   1   1   2   2 
    DQT, Row #3:   1   1   1   1   1   2   2   3 
    DQT, Row #4:   1   1   1   1   2   2   3   3 
    DQT, Row #5:   1   1   1   2   2   3   3   3 
    DQT, Row #6:   1   1   2   2   3   3   3   3 
    DQT, Row #7:   2   2   2   3   3   3   3   3 
    Approx quality factor = 98.11 (scaling=3.79 variance=4.10)
 
*** Marker: DQT ***
  Define a Quantization Table.
  OFFSET: 0x00006182
  Table length = 67
  ----
  Precision=8 bits
  Destination ID=1 (Chrominance)
    DQT, Row #0:   1   1   1   2   3   3   3   3 
    DQT, Row #1:   1   1   1   2   3   3   3   3 
    DQT, Row #2:   1   1   2   3   3   3   3   3 
    DQT, Row #3:   2   2   3   3   3   3   3   3 
    DQT, Row #4:   3   3   3   3   3   3   3   3 
    DQT, Row #5:   3   3   3   3   3   3   3   3 
    DQT, Row #6:   3   3   3   3   3   3   3   3 
    DQT, Row #7:   3   3   3   3   3   3   3   3 
    Approx quality factor = 98.36 (scaling=3.29 variance=0.42)
 
*** Marker: SOF0 (Baseline DCT) ***
  OFFSET: 0x000061C7
  Frame header length = 17
  Precision = 8
  Number of Lines = 2560
  Samples per Line = 1920
  Image Size = 1920 x 2560
  Raw Image Orientation = Portrait
  Number of Img components = 3
    Component[1]: ID=0x01, Samp Fac=0x11 (Subsamp 1 x 1), Quant Tbl Sel=0x00 (Lum: Y)
    Component[2]: ID=0x02, Samp Fac=0x11 (Subsamp 1 x 1), Quant Tbl Sel=0x01 (Chrom: Cb)
    Component[3]: ID=0x03, Samp Fac=0x11 (Subsamp 1 x 1), Quant Tbl Sel=0x01 (Chrom: Cr)

[Paddy]

part two...

*** Marker: DHT (Define Huffman Table) ***
  OFFSET: 0x000061DA
  Huffman table length = 31
  ----
  Destination ID = 0
  Class = 0 (DC / Lossless Table)
    Codes of length 01 bits (000 total): 
    Codes of length 02 bits (001 total): 00 
    Codes of length 03 bits (005 total): 01 02 03 04 05 
    Codes of length 04 bits (001 total): 06 
    Codes of length 05 bits (001 total): 07 
    Codes of length 06 bits (001 total): 08 
    Codes of length 07 bits (001 total): 09 
    Codes of length 08 bits (001 total): 0A 
    Codes of length 09 bits (001 total): 0B 
    Codes of length 10 bits (000 total): 
    Codes of length 11 bits (000 total): 
    Codes of length 12 bits (000 total): 
    Codes of length 13 bits (000 total): 
    Codes of length 14 bits (000 total): 
    Codes of length 15 bits (000 total): 
    Codes of length 16 bits (000 total): 
    Total number of codes: 012

 
*** Marker: DHT (Define Huffman Table) ***
  OFFSET: 0x000061FB
  Huffman table length = 181
  ----
  Destination ID = 0
  Class = 1 (AC Table)
    Codes of length 01 bits (000 total): 
    Codes of length 02 bits (002 total): 01 02 
    Codes of length 03 bits (001 total): 03 
    Codes of length 04 bits (003 total): 00 04 11 
    Codes of length 05 bits (003 total): 05 12 21 
    Codes of length 06 bits (002 total): 31 41 
    Codes of length 07 bits (004 total): 06 13 51 61 
    Codes of length 08 bits (003 total): 07 22 71 
    Codes of length 09 bits (005 total): 14 32 81 91 A1 
    Codes of length 10 bits (005 total): 08 23 42 B1 C1 
    Codes of length 11 bits (004 total): 15 52 D1 F0 
    Codes of length 12 bits (004 total): 24 33 62 72 
    Codes of length 13 bits (000 total): 
    Codes of length 14 bits (000 total): 
    Codes of length 15 bits (001 total): 82 
    Codes of length 16 bits (125 total): 09 0A 16 17 18 19 1A 25 26 27 28 29 2A 34 35 36 
                                         37 38 39 3A 43 44 45 46 47 48 49 4A 53 54 55 56 
                                         57 58 59 5A 63 64 65 66 67 68 69 6A 73 74 75 76 
                                         77 78 79 7A 83 84 85 86 87 88 89 8A 92 93 94 95 
                                         96 97 98 99 9A A2 A3 A4 A5 A6 A7 A8 A9 AA B2 B3 
                                         B4 B5 B6 B7 B8 B9 BA C2 C3 C4 C5 C6 C7 C8 C9 CA 
                                         D2 D3 D4 D5 D6 D7 D8 D9 DA E1 E2 E3 E4 E5 E6 E7 
                                         E8 E9 EA F1 F2 F3 F4 F5 F6 F7 F8 F9 FA 
    Total number of codes: 162

[Paddy]

final bit...

*** Marker: DHT (Define Huffman Table) ***
  OFFSET: 0x000062B2
  Huffman table length = 31
  ----
  Destination ID = 1
  Class = 0 (DC / Lossless Table)
    Codes of length 01 bits (000 total): 
    Codes of length 02 bits (003 total): 00 01 02 
    Codes of length 03 bits (001 total): 03 
    Codes of length 04 bits (001 total): 04 
    Codes of length 05 bits (001 total): 05 
    Codes of length 06 bits (001 total): 06 
    Codes of length 07 bits (001 total): 07 
    Codes of length 08 bits (001 total): 08 
    Codes of length 09 bits (001 total): 09 
    Codes of length 10 bits (001 total): 0A 
    Codes of length 11 bits (001 total): 0B 
    Codes of length 12 bits (000 total): 
    Codes of length 13 bits (000 total): 
    Codes of length 14 bits (000 total): 
    Codes of length 15 bits (000 total): 
    Codes of length 16 bits (000 total): 
    Total number of codes: 012

 
*** Marker: DHT (Define Huffman Table) ***
  OFFSET: 0x000062D3
  Huffman table length = 181
  ----
  Destination ID = 1
  Class = 1 (AC Table)
    Codes of length 01 bits (000 total): 
    Codes of length 02 bits (002 total): 00 01 
    Codes of length 03 bits (001 total): 02 
    Codes of length 04 bits (002 total): 03 11 
    Codes of length 05 bits (004 total): 04 05 21 31 
    Codes of length 06 bits (004 total): 06 12 41 51 
    Codes of length 07 bits (003 total): 07 61 71 
    Codes of length 08 bits (004 total): 13 22 32 81 
    Codes of length 09 bits (007 total): 08 14 42 91 A1 B1 C1 
    Codes of length 10 bits (005 total): 09 23 33 52 F0 
    Codes of length 11 bits (004 total): 15 62 72 D1 
    Codes of length 12 bits (004 total): 0A 16 24 34 
    Codes of length 13 bits (000 total): 
    Codes of length 14 bits (001 total): E1 
    Codes of length 15 bits (002 total): 25 F1 
    Codes of length 16 bits (119 total): 17 18 19 1A 26 27 28 29 2A 35 36 37 38 39 3A 43 
                                         44 45 46 47 48 49 4A 53 54 55 56 57 58 59 5A 63 
                                         64 65 66 67 68 69 6A 73 74 75 76 77 78 79 7A 82 
                                         83 84 85 86 87 88 89 8A 92 93 94 95 96 97 98 99 
                                         9A A2 A3 A4 A5 A6 A7 A8 A9 AA B2 B3 B4 B5 B6 B7 
                                         B8 B9 BA C2 C3 C4 C5 C6 C7 C8 C9 CA D2 D3 D4 D5 
                                         D6 D7 D8 D9 DA E2 E3 E4 E5 E6 E7 E8 E9 EA F2 F3 
                                         F4 F5 F6 F7 F8 F9 FA 
    Total number of codes: 162

 
*** Marker: SOS (Start of Scan) ***
  OFFSET: 0x0000638A
  Scan header length = 12
  Number of img components = 3
    Component[1]: selector=0x01, table=0x00
    Component[2]: selector=0x02, table=0x11
    Component[3]: selector=0x03, table=0x11
  Spectral selection = 0 .. 63
  Successive approximation = 0x00


*** Decoding SCAN Data ***
  OFFSET: 0x00006396
  Scan Decode Mode: Full IDCT (AC + DC)

  Scan Data terminated by marker 0xFFD9 @ 0x00370F8D.0

  Compression stats:
    Compression Ratio:  4.12:1
    Bits per pixel:     5.83:1

  Huffman code histogram stats:
    Huffman Table: (Dest ID: 0, Class: DC)
      # codes of length 01 bits:        0 (  0%)
      # codes of length 02 bits:     4482 (  6%)
      # codes of length 03 bits:    44788 ( 58%)
      # codes of length 04 bits:    11141 ( 15%)
      # codes of length 05 bits:     8696 ( 11%)
      # codes of length 06 bits:     5163 (  7%)
      # codes of length 07 bits:     1971 (  3%)
      # codes of length 08 bits:      458 (  1%)
      # codes of length 09 bits:      101 (  0%)
      # codes of length 10 bits:        0 (  0%)
      # codes of length 11 bits:        0 (  0%)
      # codes of length 12 bits:        0 (  0%)
      # codes of length 13 bits:        0 (  0%)
      # codes of length 14 bits:        0 (  0%)
      # codes of length 15 bits:        0 (  0%)
      # codes of length 16 bits:        0 (  0%)

    Huffman Table: (Dest ID: 1, Class: DC)
      # codes of length 01 bits:        0 (  0%)
      # codes of length 02 bits:    72570 ( 47%)
      # codes of length 03 bits:    25461 ( 17%)
      # codes of length 04 bits:    22123 ( 14%)
      # codes of length 05 bits:    15582 ( 10%)
      # codes of length 06 bits:    10060 (  7%)
      # codes of length 07 bits:     5651 (  4%)
      # codes of length 08 bits:     1842 (  1%)
      # codes of length 09 bits:      255 (  0%)
      # codes of length 10 bits:       56 (  0%)
      # codes of length 11 bits:        0 (  0%)
      # codes of length 12 bits:        0 (  0%)
      # codes of length 13 bits:        0 (  0%)
      # codes of length 14 bits:        0 (  0%)
      # codes of length 15 bits:        0 (  0%)
      # codes of length 16 bits:        0 (  0%)

    Huffman Table: (Dest ID: 0, Class: AC)
      # codes of length 01 bits:        0 (  0%)
      # codes of length 02 bits:  1176518 ( 46%)
      # codes of length 03 bits:   273177 ( 11%)
      # codes of length 04 bits:   479321 ( 19%)
      # codes of length 05 bits:   289363 ( 11%)
      # codes of length 06 bits:   111224 (  4%)
      # codes of length 07 bits:   104585 (  4%)
      # codes of length 08 bits:    46488 (  2%)
      # codes of length 09 bits:    32987 (  1%)
      # codes of length 10 bits:    15676 (  1%)
      # codes of length 11 bits:     9361 (  0%)
      # codes of length 12 bits:     1809 (  0%)
      # codes of length 13 bits:        0 (  0%)
      # codes of length 14 bits:        0 (  0%)
      # codes of length 15 bits:      165 (  0%)
      # codes of length 16 bits:     4095 (  0%)

    Huffman Table: (Dest ID: 1, Class: AC)
      # codes of length 01 bits:        0 (  0%)
      # codes of length 02 bits:   814068 ( 34%)
      # codes of length 03 bits:   312704 ( 13%)
      # codes of length 04 bits:   453866 ( 19%)
      # codes of length 05 bits:   356472 ( 15%)
      # codes of length 06 bits:   179951 (  7%)
      # codes of length 07 bits:    77525 (  3%)
      # codes of length 08 bits:    76567 (  3%)
      # codes of length 09 bits:    89992 (  4%)
      # codes of length 10 bits:    26244 (  1%)
      # codes of length 11 bits:    10872 (  0%)
      # codes of length 12 bits:      293 (  0%)
      # codes of length 13 bits:        0 (  0%)
      # codes of length 14 bits:     9206 (  0%)
      # codes of length 15 bits:     4970 (  0%)
      # codes of length 16 bits:     1320 (  0%)

  YCC clipping in DC:
    Y  component: [<0=    0] [>255=    0]
    Cb component: [<0=    0] [>255=    0]
    Cr component: [<0=    0] [>255=    0]

  RGB clipping in DC:
    R  component: [<0=    0] [>255=    0]
    G  component: [<0=    0] [>255=    0]
    B  component: [<0=    0] [>255=    0]

  Finished Decoding SCAN Data
    Number of RESTART markers decoded: 0
    Next position in scan buffer: Offset 0x00370F8C.2

 
*** Marker: EOI (End of Image) ***
  OFFSET: 0x00370F8F


*** Embedded JPEG Thumbnail ***
  Offset: 0x0000050E
  Length: 0x00001480 (5248)

  * Embedded Thumb Marker: SOI

  * Embedded Thumb Marker: DQT
    Length = 67
    ----
    Precision=0 bits
    Destination ID=0 (Luminance)
      DQT, Row #0:   8   6   5   8  12  20  26  31 
      DQT, Row #1:   6   6   7  10  13  29  30  28 
      DQT, Row #2:   7   7   8  12  20  29  35  28 
      DQT, Row #3:   7   9  11  15  26  44  40  31 
      DQT, Row #4:   9  11  19  28  34  55  52  39 
      DQT, Row #5:  12  18  28  32  41  52  57  46 
      DQT, Row #6:  25  32  39  44  52  61  60  51 
      DQT, Row #7:  36  46  48  49  56  50  52  50 
  * Embedded Thumb Marker: DQT
    Length = 67
    ----
    Precision=0 bits
    Destination ID=1 (Chrominance)
      DQT, Row #0:   9   9  12  24  50  50  50  50 
      DQT, Row #1:   9  11  13  33  50  50  50  50 
      DQT, Row #2:  12  13  28  50  50  50  50  50 
      DQT, Row #3:  24  33  50  50  50  50  50  50 
      DQT, Row #4:  50  50  50  50  50  50  50  50 
      DQT, Row #5:  50  50  50  50  50  50  50  50 
      DQT, Row #6:  50  50  50  50  50  50  50  50 
      DQT, Row #7:  50  50  50  50  50  50  50  50 

  * Embedded Thumb Marker: SOF
    Frame header length = 17
    Precision = 8
    Number of Lines = 160
    Samples per Line = 120
    Image Size = 120 x 160

  * Embedded Thumb Marker: DHT
    Length = 31

  * Embedded Thumb Marker: DHT
    Length = 181

  * Embedded Thumb Marker: DHT
    Length = 31

  * Embedded Thumb Marker: DHT
    Length = 181

  * Embedded Thumb Marker: SOS
    Skipping scan data
    Skipped 4653 bytes

  * Embedded Thumb Marker: EOI

  * Embedded Thumb Signature: 0182408A81A4ABF04D4A34A8A5E98C58

*** Searching Compression Signatures ***

  Signature:           01DADDC4908E9BA57CC067EEAD54E67D
  Signature (Rotated): 01DADDC4908E9BA57CC067EEAD54E67D
  File Offset:         0 bytes
  Chroma subsampling:  1x1
  EXIF Make/Model:     OK   [OLYMPUS CORPORATION] [E-1]
  EXIF Makernotes:     NONE
  EXIF Software:       OK   [Microsoft Windows Photo Gallery 6.0.6000.16386]

  Searching Compression Signatures: (3314 built-in, 0 user(*) )

          EXIF.Make / Software        EXIF.Model                            Quality           Subsamp Match?
          -------------------------   -----------------------------------   ----------------  --------------
     SW :[Adobe Photoshop          ]                                       [Save As 12      ]                  

  NOTE: Photoshop IRB detected
  NOTE: EXIF Software field recognized as from editor
  ASSESSMENT: Image is processed/edited

Can anyone interpret this?

[Paddy]

In all those lines of code, perhaps this is the only one that is relevent...

EXIF IFD1 @ Absolute x[000004B0]
Dir Length = x[0006]
[Compression ] = 6
[XResolution ] = 1/72
[YResolution ] = 1/72
[ResolutionUnit ] = 2
[JpegIFOffset ] = 1264
[JpegIFByteCount ] = 5248
Offset to Next IFD = [00000000]

A quick google suggests that there are 12 levels of JPEG compression, so does this mean that the files are 50% compressed?

hmm...

Compression stats:
Compression Ratio: 4.12:1
Bits per pixel: 5.83:1

Is this acceptable for a professional photoshoot with supposedly RAW copies. I had to pay £200 for them...

[Jon P. Inghram]

There aren't "12 levels" of JPEG compression, many programs use a scale of 1 to 100. And 5.8 bits/pixel is just fine for JPEGs. An uncompressed image would be 24 bits/pixel.

The Olympus E-1 doesn't have a raw+JPEG mode, so if they really used raw and you payed for it, you should also have got .ORF (or .DNG) files too.

[Nappe1]

Interesting... I am not sure if E-1 had/has this Oly's extra jpeg compression mode, which name (of course) I can't remember right now, but I think it had 1:2.7 average compression ratio, which is much less than camera JPEG engines usually do on highest quality.

I think you could ask to get the picutures as 16 bit TIFFs, but I doubt them having much more additional value, as long as the photos are exposured correctly.

It seems that this shooter has not yet to got his hands on E-3... E-3 looks really nice by bringing at last Pro/Prosumer level body up to standards where Zuiko lenses have been all times. (It's not going to take over the world, but brings Oly to par with competition in class.)

[az]

JPEG is never uncompressed, so technically you didn't get what you asked for.

In practice, the JPGs you got are probably good enough to print - the compression could hinder more extreme image manipulation (much more contrast or lots of sharpening), though, because the block structure inherent in JPG may become obvious.

[Paddy]

UPDATE:

The store contacted me today to say that they can issue me a CD with 24bit TIFFs. As you guys have stated that the Oly E1 can't shoot in simultaneous JPEG and TIFF the compression must have been done on the camera. I assume they are going to convert the JPEG to TIFF but it must be impossible to recreate the lost data?

I am happy if they can give me the RAW images but they've already told me they dont exist. Am i missing something?

Before I accept the CD I will want to verify it with my laptop. How can I check the TIFF to see if it is simply a 'renamed' JPEG?

[Paddy]

It looks like that JPEGsnoop program (fantastic bit of kit btw) will do it, although I cant test it at work.

Does anyone have experience with it?

[MultimediaMan]

Irfanview will tell you a LOT about your pictures.

[Dr Mordrid]

Including all the EXIF information.

[Paddy]

What do you suggest I do? I assume I will receive a CD of TIFFs but I need to make sure they havn't just opened the JPEGs in an editing app and clicked save as

[az]

Open JPG in Photoshop, open TIFF as another layer, select "substract". You should be seeing JPG artifacts now. If not, the images are the same.

This is from memory, and it's been a long time since I used any real image manipulation software (and that was in german), so somebody correct me please.

[Paddy]

sorry being an idiot... how do i do that?