Images loose ICC profiles during big image rescaling introduced in WP 5.3

Since version 5.3, WordPress detects big images during upload to the media library and applies a scaling. The default threshold is 2560px, and will be applied to both the height and width, and the image will be scaled down. This scaled image will be used as the largest available size. The original image will be stored too but is not used.

This scaling of the images prevents long loading times, but it caused an issue to me when using CMYK images with an embedded ICC Profile. The scaled images had no ICC profile anymore, leading to color changes during printing of my Print PDF with CMYK images.

One can add a filter as described here: Prevent WordPress from Scaling Large Images. I had to manually search for image files with _scaled in the filename and remove this from the filename to link to the original file that is also stored on the server.

I am writing this here in case somebody runs into the same problem.

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