How to convert to JPEG correctly?

[Bushman.K]

Here are metadata dumps for each JPEG file in the same order:

Code: Select all

Image: Lens_IrfanView.jpg
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 656x330+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: JPEG
  Quality: 28
  Orientation: Undefined
  Properties:
    date:create: 2015-10-07T10:26:09-07:00
    date:modify: 2015-10-07T10:26:10-07:00
    jpeg:colorspace: 2
    jpeg:sampling-factor: 1x1,1x1,1x1
    signature: 1d72133c7c9a59a720ffb5bc564f2c5db5ae614d4db1d200b45fa7eeb1ff433c
  Artifacts:
    filename: Lens_IrfanView.jpg
    verbose: true
  Tainted: False
  Filesize: 27.6KB
  Number pixels: 216K
  Pixels per second: 72.2MB
  User time: 0.000u
  Elapsed time: 0:01.002

Code: Select all

Image: LensQ6.jpg
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 656x330+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: JPEG
  Quality: 92
  Orientation: TopLeft
  Properties:
    date:create: 2015-10-07T10:26:19-07:00
    date:modify: 2015-10-07T10:26:20-07:00
    exif:ColorSpace: 1
    exif:Compression: 6
    exif:DateTime: 2015:10:06 18:08:40
    exif:ExifImageLength: 330
    exif:ExifImageWidth: 656
    exif:ExifOffset: 168
    exif:JPEGInterchangeFormat: 306
    exif:JPEGInterchangeFormatLength: 3557
    exif:Orientation: 1
    exif:ResolutionUnit: 2
    exif:Software: Adobe Photoshop CC 2015 (Windows)
    exif:thumbnail:ResolutionUnit: 2
    exif:thumbnail:XResolution: 72/1
    exif:thumbnail:YResolution: 72/1
    exif:XResolution: 960120/10000
    exif:YResolution: 960120/10000
    jpeg:colorspace: 2
    jpeg:sampling-factor: 2x2,1x1,1x1
    signature: 747e3f08b88a2c400316cce5d73326f05f251b51d73307559b0a1bb6019779c4
  Profiles:
    Profile-8bim: 5878 bytes
    Profile-exif: 3869 bytes
    Profile-icc: 3144 bytes
      Description: sRGB IEC61966-2.1
      Manufacturer: IEC http://www.iec.ch
      Model: IEC 61966-2.1 Default RGB colour space - sRGB
      Copyright: Copyright (c) 1998 Hewlett-Packard Company
    Profile-xmp: 3335 bytes
  Artifacts:
    filename: LensQ6.jpg
    verbose: true
  Tainted: False
  Filesize: 60.8KB
  Number pixels: 216K
  Pixels per second: 6.765MB
  User time: 0.000u
  Elapsed time: 0:01.031

Code: Select all

Image: Lens_IrfanView1x1at59p3KB.jpg
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 656x330+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: JPEG
  Quality: 80
  Orientation: Undefined
  Properties:
    date:create: 2015-10-07T10:26:31-07:00
    date:modify: 2015-10-07T10:26:31-07:00
    jpeg:colorspace: 2
    jpeg:sampling-factor: 1x1,1x1,1x1
    signature: f5bb73c03f27ed0aa33bb8d44254bda78a814f4951bd888b65e7b05a84309ca4
  Artifacts:
    filename: Lens_IrfanView1x1at59p3KB.jpg
    verbose: true
  Tainted: False
  Filesize: 60.4KB
  Number pixels: 216K
  Pixels per second: 72.15MB
  User time: 0.000u
  Elapsed time: 0:01.003

Code: Select all

Image: LensQ7.jpg
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 656x330+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: JPEG
  Quality: 91
  Orientation: TopLeft
  Properties:
    date:create: 2015-10-07T10:26:39-07:00
    date:modify: 2015-10-07T10:26:40-07:00
    exif:ColorSpace: 1
    exif:Compression: 6
    exif:DateTime: 2015:10:06 18:08:57
    exif:ExifImageLength: 330
    exif:ExifImageWidth: 656
    exif:ExifOffset: 168
    exif:JPEGInterchangeFormat: 306
    exif:JPEGInterchangeFormatLength: 3557
    exif:Orientation: 1
    exif:ResolutionUnit: 2
    exif:Software: Adobe Photoshop CC 2015 (Windows)
    exif:thumbnail:ResolutionUnit: 2
    exif:thumbnail:XResolution: 72/1
    exif:thumbnail:YResolution: 72/1
    exif:XResolution: 960120/10000
    exif:YResolution: 960120/10000
    jpeg:colorspace: 2
    jpeg:sampling-factor: 1x1,1x1,1x1
    signature: 2b9c27362d8799533748e3f7f45b6d9ccb2f51a6dbde89a2d56a885ec5825efe
  Profiles:
    Profile-8bim: 5870 bytes
    Profile-exif: 3869 bytes
    Profile-icc: 3144 bytes
      Description: sRGB IEC61966-2.1
      Manufacturer: IEC http://www.iec.ch
      Model: IEC 61966-2.1 Default RGB colour space - sRGB
      Copyright: Copyright (c) 1998 Hewlett-Packard Company
    Profile-xmp: 3765 bytes
  Artifacts:
    filename: LensQ7.jpg
    verbose: true
  Tainted: False
  Filesize: 74.9KB
  Number pixels: 216K
  Pixels per second: 54.12MB
  User time: 0.000u
  Elapsed time: 0:01.003

Code: Select all

Image: LensQ8.jpg
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 656x330+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: JPEG
  Quality: 92
  Orientation: TopLeft
  Properties:
    date:create: 2015-10-07T10:26:47-07:00
    date:modify: 2015-10-07T10:26:48-07:00
    exif:ColorSpace: 1
    exif:Compression: 6
    exif:DateTime: 2015:10:06 18:09:11
    exif:ExifImageLength: 330
    exif:ExifImageWidth: 656
    exif:ExifOffset: 168
    exif:JPEGInterchangeFormat: 306
    exif:JPEGInterchangeFormatLength: 3557
    exif:Orientation: 1
    exif:ResolutionUnit: 2
    exif:Software: Adobe Photoshop CC 2015 (Windows)
    exif:thumbnail:ResolutionUnit: 2
    exif:thumbnail:XResolution: 72/1
    exif:thumbnail:YResolution: 72/1
    exif:XResolution: 960120/10000
    exif:YResolution: 960120/10000
    jpeg:colorspace: 2
    jpeg:sampling-factor: 1x1,1x1,1x1
    signature: 3842850bab4acc662a335bbbe42899b6189ce367cdec7ebebd7ae7c48a4b621d
  Profiles:
    Profile-8bim: 5870 bytes
    Profile-exif: 3869 bytes
    Profile-icc: 3144 bytes
      Description: sRGB IEC61966-2.1
      Manufacturer: IEC http://www.iec.ch
      Model: IEC 61966-2.1 Default RGB colour space - sRGB
      Copyright: Copyright (c) 1998 Hewlett-Packard Company
    Profile-xmp: 3765 bytes
  Artifacts:
    filename: LensQ8.jpg
    verbose: true
  Tainted: False
  Filesize: 87.6KB
  Number pixels: 216K
  Pixels per second: 54.12MB
  User time: 0.000u
  Elapsed time: 0:01.003

Code: Select all

Image: LensQ9.jpg
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 656x330+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: JPEG
  Quality: 93
  Orientation: TopLeft
  Properties:
    date:create: 2015-10-07T10:26:55-07:00
    date:modify: 2015-10-07T10:26:56-07:00
    exif:ColorSpace: 1
    exif:Compression: 6
    exif:DateTime: 2015:10:06 18:17:35
    exif:ExifImageLength: 330
    exif:ExifImageWidth: 656
    exif:ExifOffset: 168
    exif:JPEGInterchangeFormat: 306
    exif:JPEGInterchangeFormatLength: 3557
    exif:Orientation: 1
    exif:ResolutionUnit: 2
    exif:Software: Adobe Photoshop CC 2015 (Windows)
    exif:thumbnail:ResolutionUnit: 2
    exif:thumbnail:XResolution: 72/1
    exif:thumbnail:YResolution: 72/1
    exif:XResolution: 960120/10000
    exif:YResolution: 960120/10000
    jpeg:colorspace: 2
    jpeg:sampling-factor: 1x1,1x1,1x1
    signature: ed54b70a853a48df8f5415c354999fa15baf9b87ada9de6bf338cc8ef0d892f2
    xmpMM:DerivedFrom: 
  Profiles:
    Profile-8bim: 5866 bytes
    Profile-exif: 3869 bytes
    Profile-icc: 3144 bytes
      Description: sRGB IEC61966-2.1
      Manufacturer: IEC http://www.iec.ch
      Model: IEC 61966-2.1 Default RGB colour space - sRGB
      Copyright: Copyright (c) 1998 Hewlett-Packard Company
    Profile-xmp: 5019 bytes
  Artifacts:
    filename: LensQ9.jpg
    verbose: true
  Tainted: False
  Filesize: 98.7KB
  Number pixels: 216K
  Pixels per second: 54.12MB
  User time: 0.000u
  Elapsed time: 0:01.003

Code: Select all

Image: LensSFW50.jpg
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 656x330+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: JPEG
  Quality: 82
  Orientation: Undefined
  Properties:
    date:create: 2015-10-07T10:27:03-07:00
    date:modify: 2015-10-07T10:27:03-07:00
    jpeg:colorspace: 2
    jpeg:sampling-factor: 2x2,1x1,1x1
    signature: af11be096643def49a9f6d2a33ae944c93fbe04a2604547a64702eeb3f38a83d
    xmpMM:DerivedFrom: 
  Profiles:
    Profile-APP12: 15 bytes
    Profile-exif: 22 bytes
    Profile-xmp: 878 bytes
  Artifacts:
    filename: LensSFW50.jpg
    verbose: true
  Tainted: False
  Filesize: 39.7KB
  Number pixels: 216K
  Pixels per second: 54.12MB
  User time: 0.000u
  Elapsed time: 0:01.003

Code: Select all

Image: LensSFW51.jpg
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 656x330+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: JPEG
  Quality: 82
  Orientation: Undefined
  Properties:
    date:create: 2015-10-07T10:27:12-07:00
    date:modify: 2015-10-07T10:27:12-07:00
    jpeg:colorspace: 2
    jpeg:sampling-factor: 1x1,1x1,1x1
    signature: 6693b09a59f5b899f80243b9392959c024ce063b7e15f29c617e5be208742df1
    xmpMM:DerivedFrom: 
  Profiles:
    Profile-APP12: 15 bytes
    Profile-exif: 22 bytes
    Profile-xmp: 878 bytes
  Artifacts:
    filename: LensSFW51.jpg
    verbose: true
  Tainted: False
  Filesize: 53.1KB
  Number pixels: 216K
  Pixels per second: 54.12MB
  User time: 0.016u
  Elapsed time: 0:01.003

[Bushman.K]

Speaking of optimization tools, I'd say, that you don't need any commercial tools unless you want to play with so called variable compression, when amount of details loss in JPEG file is proportional to something (custom mask, details mask or whatever). In general case, mechanisms, built into IrfanView, XnView, or standalone RIOT doing their job. Unfortunately, I'm not using Mac, so I can't tell anything about tools for this OS.