Requisite sharp features/API to enable configurable image compression?

dopplerfto · November 1, 2021, 8:18am

I was writing a new post on my photo blog when I discovered that my images look like trash once I open the preview in another window. That’s when I discovered

and consequently

github.com/lovell/sharp

Image transformation with no compression/resizing looses quality

opened 04:51PM - 29 Aug 18 UTC

closed 04:52PM - 30 Aug 18 UTC

naz

question

When reading and jpeg image from file and writing it back to a different file wi…thout applying any transformations it loses size. Example: ``` sharp('original.jpg').withMetadata().toFile('transformed.jpg'); ``` During the tranformation output is following: ``` vips warning: exif: bad exif meta "exif-ifd3-GPSVersionID" ``` The version or sharp that is being used: `v0.20.7` `file` output: ``` file *.jpg original.jpg: JPEG image data, Exif standard: [TIFF image data, big-endian, direntries=16, height=3968, bps=0, width=2976], baseline, precision 8, 2976x3968, frames 3 transformed.jpg: JPEG image data, JFIF standard 1.01, aspect ratio, density 1x1, segment length 16, Exif Standard: [TIFF image data, big-endian, direntries=15, height=3968, bps=0, width=2976], baseline, precision 8, 2976x3968, frames 3 ``` The image that is being transformed `original.jpg`: ![original](https://user-images.githubusercontent.com/675397/44801874-8cd77f80-abba-11e8-9782-fbfcb10be2e9.jpg) Transformed image `transformed.jpg`: ![transformed](https://user-images.githubusercontent.com/675397/44801882-982aab00-abba-11e8-90c0-f9ee92f3c7ab.jpg) Node versoin: `v8.11.4` OS: `Ubuntu 18.04` Is this an expected behavior? What options could be specified to avoid any transformatios but still use sharp for writing the output file (this is needed due to specifics of wrapper library implementation)?

And I see that Ghost doesn’t have any codepaths to use other-than-default compression/quality right now:

github.com

TryGhost/Utils/blob/ba37890be49efc59381b17b9c78e0c9e2ed92eaf/packages/image-transform/lib/transform.js#L58


      
          
          /**
           * Resize an image
           *
           * @param {Buffer} originalBuffer image to resize
           * @param {{width, height}} options
           * @returns {Buffer} the resizedBuffer
           */
          const unsafeResizeFromBuffer = (originalBuffer, {width, height} = {}) => {
              const sharp = require('sharp');
              return sharp(originalBuffer)
                  .resize(width, height, {
                      // CASE: dont make the image bigger than it was
                      withoutEnlargement: true
                  })
                  // CASE: Automatically remove metadata and rotate based on the orientation.
                  .rotate()
                  .toBuffer()
                  .then((resizedBuffer) => {
                      return resizedBuffer.length < originalBuffer.length ? resizedBuffer : originalBuffer;
                  });

I don’t want my images to look like trash (and I also don’t want to force my readers to download PNGs instead of a more reasonable format). So what kind of API would need to exist in order for Ghost to provide some configurability here? Just “default” / “better” / “best”? Something else? Would there be a desire to support even more aggressive compression than the default?

John · November 1, 2021, 4:48pm

Compression and optimisation config is documented here.

If you’re not satisfied with those options you can configure an external storage adapter, such as cloudinary, to host and optimise media externally to Ghost

piratefache · May 7, 2022, 9:20pm

Any news? @John the compression/quality feature is not in the documentation because it has not been implemented yet.

The default quality for JPEG files is 80% which is way too low for me. It has been a while now and I don’t see any other possibility than uploading png files images in order to preserve the image quality…

Did you plan to add this option soon ?

John · May 9, 2022, 3:43pm

From the link directly above:

Topic		Replies	Views
Image Compression Configuration Developer help	9	2371	August 23, 2022
Responsive images are not generated [Resolved] Developer help	5	1287	March 8, 2019
WebM/mp4 support for feature image Ideas	2	378	May 27, 2022
Upload Images - Error 502 Installation	6	826	March 4, 2020
Disable image optimization? Developer help	13	1887	December 7, 2021

Requisite sharp features/API to enable configurable image compression?

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