We recently hit on some exciting compressor development, and I thought I'd throw in some fun tests. Here are the results (I'm just including selector images because I think they're pretty and interesting).
These are experiments for the ETC1 and DXT formats. ETC1 covers most Android devices, DXT covers most desktop platforms.
Picture 1: https://upload.wikimedia.org/wikipedia/commons/2/27/Flowers_in_sunset_in_Massachusetts.jpg
Original

Compressed to ETC1

Selector

Compressed to ETC1
Selector
Picture 3: https://twitter.com/jembawls/status/773421465085640704
Original
Compressed to ETC1

Compressed to DXT1
Selector