Hi, @lftoma, there is a thought experiment in data compression of:
- Can a single compression algorithm compress all files?
As with all thought experiments the value is in solving the puzzle yourself but I’m going to reveal to the answer:
- No single compression algorithm can compress all files.
Sometimes attempting to “compress” a file only makes it bigger. This is especially true for already compressed data and PNG files are already very well compressed.
I’m rambling a bit. Why do I mention all this?
Because if you brotli compress that particular PNG file it gets bigger. Really.
Here is the original file and the same file compressed with brotli:
-rw-r--r-- 1 luke staff 33214 Aug 12 23:06 hero-1.be81a297.png
-rw-r--r-- 1 luke staff 33218 Aug 12 23:06 hero-1.be81a297.png.br
This file is four bytes bigger with brotli so it isn’t used. You are likely to find the same with most if not all of your PNG files.
To summarize, if a file will be bigger using brotli compression (which is very common for PNGs), we won’t use it. If there are other questions, please let us know.