Just did a quick test. On the high quality setting it reduced a 3MB input jpeg image to 0.5MB with a very noticable loss in quality. To me at least that qualifies as “extreme”. Why not just have a third option allowing you to send images without recompression? In order to do that you currently have to trick Signal by e.g. changing the file extension or sending the images hidden in a zip file, which ist just terrible UX.