Yes, some gains come from stripping metadata, but structural compression means optimizing how image data is encoded, like better Huffman tables for JPGs or smarter filtering for PNGs.
That's not compression, that's just deleting people's data.
structural compression means optimizing how image data is encoded, like better Huffman tables for JPGs or smarter filtering for PNGs.
I think that's just called compression.
How are you getting better huffman tables for JPGs and how are you doing 'smarter' filtering for PNGs ?
I'm asking for deeper technical explanations because not only would beating current image compression libraries be a technical feat, a lot of people in this thread think that you aren't actually doing anything differently.