PSA regarding wallpapers: Make sure your BMP has a bit depth of 24

I was cropping some manga panels to make into wallpapers (so black and white images), using paint.net on Windows. When saving, I had bit depth set to "auto-detect", and it saved them with a bit depth of 8.

This caused the wallpapers to be rendered inverted on the device, white pixels became black and vice versa, including grayscale pixels. But even after attempting to invert the image myself, it displayed them "as-is", so still black background with white outlines.

After looking at community wallpapers, I figured out that the bitmaps need to be saved with a bit depth of 24. I have not attempted other settings, as this one works.

Wrote out the explanation so hopefully someone else with this issue can find this post!