Specific jpeg images result in very strange saved images (corrupted?)

[LarsWesselius]

Prerequisites

• I have written a descriptive issue title
• I have verified that I am running the latest version of ImageSharp
• I have verified if the problem exist in both DEBUG and RELEASE mode
• I have searched open and closed issues to ensure it has not already been reported

Description

When loading an image using Image.Load and saving it again, using image.Save(). the resulting image is very different from the original, loaded image without doing any mutations.

Steps to Reproduce

.NET Core 2.1 Console app. Use
using (Image<Rgba32> image = Image.Load("8.jpg")) { image.Save("8-saved.jpg"); }
As the only code in Main and run with 8.jpg in your working directory (see attached).

This is the image being loaded (8.jpg):

This is the resulting image after saving:

System Configuration

• ImageSharp version: SixLabors.ImageSharp v1.0.0-beta0006
• Other ImageSharp packages and versions: None
• Environment (Operating system, version and so on): Windows 10, latest. .NET Core 2.1 console application
• .NET Framework version: .NET Core 2.1
• Additional information:

[JimBobSquarePants]

JpegSnoop Output

It's YccK I wonder if we are not parsing the color mode properly. cc/ @antonfirsov

Nope. Everything looks fine. It's happening after the scan decoder I think.

JPEGsnoop 1.8.0 by Calvin Hass
  http://www.impulseadventure.com/photo/
  -------------------------------------

  Filename: [C:\Users\james\source\repos\ImageSharp.Test\images\cutoff.jpg]
  Filesize: [31527] Bytes

Start Offset: 0x00000000
*** Marker: SOI (xFFD8) ***
  OFFSET: 0x00000000
 
*** Marker: APP0 (xFFE0) ***
  OFFSET: 0x00000002
  Length     = 16
  Identifier = [JFIF]
  version    = [1.1]
  density    = 72 x 72 DPI (dots per inch)
  thumbnail  = 0 x 0
 
*** Marker: APP14 (xFFEE) ***
  OFFSET: 0x00000014
  Length            = 14
  DCTEncodeVersion  = 100
  APP14Flags0       = 0
  APP14Flags1       = 0
  ColorTransform    = 0 [Unknown (RGB or CMYK)]
 
*** Marker: DQT (xFFDB) ***
  Define a Quantization Table.
  OFFSET: 0x00000024
  Table length = 67
  ----
  Precision=8 bits
  Destination ID=0 (Luminance)
    DQT, Row #0:   2   2   1   2   3   6   7   9 
    DQT, Row #1:   2   2   2   3   4   8   8   8 
    DQT, Row #2:   2   2   2   3   6   8  10   8 
    DQT, Row #3:   2   2   3   4   7  12  11   9 
    DQT, Row #4:   3   3   5   8  10  15  14  11 
    DQT, Row #5:   3   5   8   9  11  15  16  13 
    DQT, Row #6:   7   9  11  12  14  17  17  14 
    DQT, Row #7:  10  13  13  14  16  14  14  14 
    Approx quality factor = 92.96 (scaling=14.08 variance=1.37)
 
*** Marker: SOF0 (Baseline DCT) (xFFC0) ***
  OFFSET: 0x00000069
  Frame header length = 20
  Precision = 8
  Number of Lines = 290
  Samples per Line = 400
  Image Size = 400 x 290
  Raw Image Orientation = Landscape
  Number of Img components = 4
    Component[1]: ID=0x43, Samp Fac=0x22 (Subsamp 1 x 1), Quant Tbl Sel=0x00 (Y)
    Component[2]: ID=0x4D, Samp Fac=0x11 (Subsamp 2 x 2), Quant Tbl Sel=0x00 (Cb)
    Component[3]: ID=0x59, Samp Fac=0x11 (Subsamp 2 x 2), Quant Tbl Sel=0x00 (Cr)
    Component[4]: ID=0x4B, Samp Fac=0x11 (Subsamp 2 x 2), Quant Tbl Sel=0x00 (K)
 
*** Marker: DHT (Define Huffman Table) (xFFC4) ***
  OFFSET: 0x0000007F
  Huffman table length = 29
  ----
  Destination ID = 0
  Class = 0 (DC / Lossless Table)
    Codes of length 01 bits (001 total): 00 
    Codes of length 02 bits (000 total): 
    Codes of length 03 bits (002 total): 05 06 
    Codes of length 04 bits (002 total): 04 07 
    Codes of length 05 bits (003 total): 02 03 08 
    Codes of length 06 bits (001 total): 09 
    Codes of length 07 bits (001 total): 01 
    Codes of length 08 bits (000 total): 
    Codes of length 09 bits (000 total): 
    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: 010

 
*** Marker: DHT (Define Huffman Table) (xFFC4) ***
  OFFSET: 0x0000009E
  Huffman table length = 65
  ----
  Destination ID = 0
  Class = 1 (AC Table)
    Codes of length 01 bits (000 total): 
    Codes of length 02 bits (001 total): 01 
    Codes of length 03 bits (003 total): 02 03 04 
    Codes of length 04 bits (003 total): 00 05 11 
    Codes of length 05 bits (003 total): 06 12 21 
    Codes of length 06 bits (002 total): 07 31 
    Codes of length 07 bits (004 total): 13 22 41 51 
    Codes of length 08 bits (004 total): 08 14 32 61 
    Codes of length 09 bits (005 total): 15 23 42 71 81 
    Codes of length 10 bits (002 total): 91 A1 
    Codes of length 11 bits (005 total): 16 33 52 B1 C1 
    Codes of length 12 bits (004 total): 09 24 62 D1 
    Codes of length 13 bits (001 total): 72 
    Codes of length 14 bits (003 total): 17 43 E1 
    Codes of length 15 bits (005 total): 18 25 34 82 F0 
    Codes of length 16 bits (001 total): F1 
    Total number of codes: 046

 
*** Marker: SOS (Start of Scan) (xFFDA) ***
  OFFSET: 0x000000E1
  Scan header length = 14
  Number of img components = 4
    Component[1]: selector=0x43, table=0(DC),0(AC)
    Component[2]: selector=0x4D, table=0(DC),0(AC)
    Component[3]: selector=0x59, table=0(DC),0(AC)
    Component[4]: selector=0x4B, table=0(DC),0(AC)
  Spectral selection = 0 .. 63
  Successive approximation = 0x00

  NOTE: Scan parsing doesn't support CMYK files yet.
 
*** Marker: EOI (End of Image) (xFFD9) ***
  OFFSET: 0x00007B25


*** Searching Compression Signatures ***

  Signature:           011D2972762547222591CBAA7C61AF23
  Signature (Rotated): 01A6F243D0894ED6B08CD932F2C5F096
  File Offset:         0 bytes
  Chroma subsampling:  ?x?
  EXIF Make/Model:     NONE
  EXIF Makernotes:     NONE
  EXIF Software:       NONE

  Searching Compression Signatures: (3347 built-in, 0 user(*) )

          EXIF.Make / Software        EXIF.Model                            Quality           Subsamp Match?
          -------------------------   -----------------------------------   ----------------  --------------
     SW :[IJG Library              ]                                       [093 Gray        ]                  

    The following IJG-based editors also match this signature:
     SW :[GIMP                     ]                                       [093 Gray        ]                  
     SW :[IrfanView                ]                                       [093 Gray        ]                  
     SW :[idImager                 ]                                       [093 Gray        ]                  
     SW :[FastStone Image Viewer   ]                                       [093 Gray        ]                  
     SW :[NeatImage                ]                                       [093 Gray        ]                  
     SW :[Paint.NET                ]                                       [093 Gray        ]                  
     SW :[Photomatix               ]                                       [093 Gray        ]                  
     SW :[XnView                   ]                                       [093 Gray        ]                  

  Based on the analysis of compression characteristics and EXIF metadata:

  ASSESSMENT: Class 1 - Image is processed/edited

  This may be a new software editor for the database.
  If this file is processed, and editor doesn't appear in list above,
  PLEASE ADD TO DATABASE with [Tools->Add Camera to DB]

[LarsWesselius]

Opening and saving it in Paint for example produces a smaller jpeg which does work in ImageSharp.

[JimBobSquarePants]

@LarsWesselius I imagine paint is reencoding it to YCbCr. Just running a debug pass on the image now.