Open Radar

 
Summary:
Resources take up a good portion of the operating system size. PNG/JPEG images in particular can be fairly large but can and should be optimised using tools such as OptiPNG, ZopfliPNG, and MozJPEG. These are lossless optimisers; the image does not lose quality, and do not take more CPU time to decode.

Steps to Reproduce:
1. Create a sample of system graphics, for example:

find /Applications/{Photos,Safari}.app /Library/{Desktop\ Pictures,Screen\ Savers,User\ Pictures} -name \*.png -or -name \*.jpg -or -name \*.jpeg > imgs

2. Make copies of the files so they can be modified:

mkdir /tmp/test; while read i; do ext="${i##*.}"; name="$(mktemp /tmp/test/XXXXXX.$ext)"; cp "$i" "$name"; done < imgs

4. Install ImageOptim (https://imageoptim.com/), and then drag the folder onto the app.

Expected Results:
Images are already optimised. ImageOptim displays "×" icon beside most images, and only manages to optimise a very low percentage (<5%) on average.

Actual Results:
The total size of /tmp/test is 592 MB. After running ImageOptim, it is 545 MB, saving 47 MB, and 30% per file on average. This is of course excluding other formats such as GIF, TIFF, and ICNS that could also possibly be optimised.

Version:
OS X 10.11.5 (15F34)

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Configuration:


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