@derangedhermit
Well, here are a pair of images for you to fiddle with if you want. One pretty dark-toned, the other with lots of white. They are both 1200px wide
File sizes seem huge after using images 600px wide!
Each one was saved with 4 different settings---
Source decreased to 256 shades using "Optimized Octree" algorithm, saved to PNG using "Existing Palette".
Source saved to PNG using PSP default 8-bit greyscale algorithm.
Source decreased to 8-bit greyscale, saved to jpeg with 20% compression.
Source decreased to 8-bit greyscale, saved to jpeg with 1% (minimum) compression.
You might also find interest in some of the screenshots and samples on a thread I posted earlier
https://www.mobileread.com/forums/sho...d.php?t=222916
You commented earlier about the "glare" of white areas while using Night Mode. I can't think of anything to be done about that from the user end. I imagine that the image could be created using off-white instead of pure white (e.g.: RGB 250-250-250 instead of 255-255-255) but then they would look grimy when displayed on a white background.