I stumbled appon a warning message that was thrown by PHP when handling images with GD lib (e.g. imagecreatefrompng()). The message shown was:

libpng warning: Interlace handling should be turned on when using png_read_image

This message even exists, when deactivating ‘interlace’ with the help of:

imageinterlace($img, false);

The only solution is to deactivate for the processed image(s). This is possible with ImageMagick. To deactivate interlace on all images of a folder, the following command can be used:

magick mogrify -interlace none *.png

I used ImageMagick on macos and installed it with with HomeBrew:

brew install imagemagick