After long searching I found the reason for my performance problems. The default_compressed_extensions.txt does not work out of the box on Linux systems.
Seems the comparison is case sensitive, and all pics and videos with extensions xxx.MOV, yyy.JPG, zzz.MP4 are compressed - because only .mov .jpg .mp4 are mentionen in the default_compressed_extensions.txt
Is there any good way to make this case insensitive, without doubling all the entries in the default_compressed_extensions.txt file? (and if I double it, special cases like .Jpg are not covered as well)
Don’t get me wrong - the default extensions file is really great and I appreciate it. Would just be good to handle all cases on Linux systems.