如何使用 jpegoptim 使文件大小僅為 20kb？

我嘗試過使用 jpegoptim，甚至嘗試過聯機幫助頁，但我很難過。這是我想減少到 50k 甚至打開以降低數據質量的文件 -

Image:
 Filename: shirish.jpg
 Format: JPEG (Joint Photographic Experts Group JFIF format)
 Mime type: image/jpeg
 Class: DirectClass
 Geometry: 4624x3468+0+0
 Resolution: 72x72
 Print size: 64.2222x48.1667
 Units: PixelsPerInch
 Colorspace: sRGB
 Type: TrueColor
 Base type: Undefined
 Endianness: Undefined
 Depth: 8-bit
 Channel depth:
   red: 8-bit
   green: 8-bit
   blue: 8-bit
 Channel statistics:
   Pixels: 16036032
   Red:
     min: 0  (0)
     max: 255 (1)
     mean: 119.779 (0.46972)
     standard deviation: 60.359 (0.236702)
     kurtosis: -1.33094
     skewness: -0.2895
     entropy: 0.920909
   Green:
     min: 0  (0)
     max: 255 (1)
     mean: 115.071 (0.45126)
     standard deviation: 63.5402 (0.249177)
     kurtosis: -1.51367
     skewness: -0.162973
     entropy: 0.912909
   Blue:
     min: 0  (0)
     max: 255 (1)
     mean: 114.566 (0.449277)
     standard deviation: 61.8685 (0.242621)
     kurtosis: -1.51015
     skewness: -0.101152
     entropy: 0.912805
 Image statistics:
   Overall:
     min: 0  (0)
     max: 255 (1)
     mean: 116.472 (0.456752)
     standard deviation: 61.9226 (0.242834)
     kurtosis: -1.46062
     skewness: -0.184944
     entropy: 0.915541
 Rendering intent: Perceptual
 Gamma: 0.454545
 Chromaticity:
   red primary: (0.64,0.33)
   green primary: (0.3,0.6)
   blue primary: (0.15,0.06)
   white point: (0.3127,0.329)
 Background color: white
 Border color: srgb(223,223,223)
 Matte color: grey74
 Transparent color: black
 Interlace: None
 Intensity: Undefined
 Compose: Over
 Page geometry: 4624x3468+0+0
 Dispose: Undefined
 Iterations: 0
 Compression: JPEG
 Quality: 92
 Orientation: RightTop
 Profiles:
   Profile-app4: 7600 bytes
   Profile-exif: 51509 bytes
 Properties:
   date:create: 2022-08-20T05:27:53+00:00
   date:modify: 2022-08-20T05:27:53+00:00
   exif:ApertureValue: 169/100
   exif:BrightnessValue: 264/100
   exif:ColorSpace: 1
   exif:DateTime: 2022:08:20 10:53:10
   exif:DateTimeDigitized: 2022:08:20 10:53:10
   exif:DateTimeOriginal: 2022:08:20 10:53:10
   exif:DigitalZoomRatio: 100/100
   exif:ExifOffset: 226
   exif:ExifVersion: 48, 50, 50, 48
   exif:ExposureMode: 0
   exif:ExposureProgram: 2
   exif:ExposureTime: 1/50
   exif:Flash: 0
   exif:FNumber: 180/100
   exif:FocalLength: 532/100
   exif:FocalLengthIn35mmFilm: 28
   exif:ImageLength: 3468
   exif:ImageUniqueID: I64ELODR0PM
   exif:ImageWidth: 4624
   exif:Make: samsung
   exif:MaxApertureValue: 169/100
   exif:MeteringMode: 2
   exif:Model: SM-M526B
   exif:OffsetTime: +05:30
   exif:OffsetTimeOriginal: +05:30
   exif:PhotographicSensitivity: 160
   exif:PixelXDimension: 4624
   exif:PixelYDimension: 3468
   exif:SceneCaptureType: 0
   exif:ShutterSpeedValue: 1/50
   exif:Software: M526BXXU1BVG4
   exif:thumbnail:Compression: 6
   exif:thumbnail:ImageLength: 384
   exif:thumbnail:ImageWidth: 512
   exif:thumbnail:JPEGInterchangeFormat: 782
   exif:thumbnail:JPEGInterchangeFormatLength: 50721
   exif:thumbnail:ResolutionUnit: 2
   exif:thumbnail:XResolution: 72/1
   exif:thumbnail:YResolution: 72/1
   exif:WhiteBalance: 0
   exif:YCbCrPositioning: 1
   jpeg:colorspace: 2
   jpeg:sampling-factor: 2x2,1x1,1x1
   signature: 7841c1e0cbe1aa5b79f0dea6791ffd321e2cf05715a9ab3cd210fd551c9bf355
 Artifacts:
   filename: shirish.jpg
   verbose: true
 Tainted: False
 Filesize: 3.65599MiB
 Number pixels: 16.036M
 Pixels per second: 126.41MB
 User time: 0.120u
 Elapsed time: 0:01.126
 Version: ImageMagick 6.9.11-60 Q16 x86_64 2021-01-25 https://imagemagick.org

現在我嘗試了 imagemagick convert 和 jpegoptim 來獲得一個大約 50k 的文件。我需要那個大小的文件，因為我必須把它上傳到某個地方並且有大小限制。

我使用 imagemagick 中的 identify -verbose 開關獲得了上述 exif 和照片數據。

有人可以在上面幫助我。

我確實嘗試了以下 -

$jpegoptim --size=50k shirish.jpg

我得到了一個 200 kb 的文件，而不是 50kb，這很好，但不是我想要的 :(

我什至試過——

$jpegoptim --max=10 --size=50k shirish-aadhar-2-reduced.jpg

但即使這樣也沒有產生預期的結果。

$ jpegoptim --version
jpegoptim v1.4.7  x86_64-pc-linux-gnu (Jun 20 2022)
Copyright (C) 1996-2022, Timo Kokkonen

This program comes with ABSOLUTELY NO WARRANTY. This is free software,
and you are welcome to redistirbute it under certain conditions.
See the GNU General Public License for more details.


libjpeg version: 6b  27-Mar-1998
Copyright (C) 1991-2021 The libjpeg-turbo Project and many others

期待幫助。我知道我可以使用一些線上工具，但希望可以離線使用。

您可以使用 ImageMagick 去除所有元數據並降低質量。檢查此答案以獲取更多資訊：

85

漸進式（混合壓縮）中的質量

用於優化大小（半徑 0.05 或 0.5）的非常微小的高斯模糊取決於圖片的質量和大小，這顯著

優化了 jpeg 的大小。

剝離任何評論或 EXIF 元數據

在 imagemagick 中應該是

convert -strip -interlace Plane -gaussian-blur 0.05 -quality 85% source.jpg result.jpg

或在較新的版本中：

magick source.jpg -strip -interlace Plane -gaussian-blur 0.05 -quality 85% result.jpg

你可以玩-quality數字。但是將 16MP 圖像壓縮到 50k 會產生不那麼令人愉快的結果。

引用自：https://unix.stackexchange.com/questions/714248