This may be a limitation of the Windows clipboard and not a DO setting, but I use the Awesome Screenshot plugin for Chrome and I noticed that when I save a screenshot using the plugin, the bit depth of the image is 32 bits. However, when I copy the image to clipboard (via the plugin) and then paste it in a lister, the filesize is about 1/3rd smaller and the image is 24 bits.
Is that a setting that can be changed?
In settings->Miscellaneous->Advanced I see that the pasted image type can be changed through the clipboard_image_paste setting, but I don't see anything about bit depth.
If you're pasting in Opus to a BMP file, Opus will save the bitmap data in the clipboard as-is, so if a 32-bit bitmap is in the clipboard you'll get a 32-bit BMP file. If you get a 24-bit BMP file, whatever set the clipboard data must have set it as 24-bit.
If you're pasting in Opus to a PNG file, Opus will use the lowest bitdepth that can still represent the entire image without any modification, so you get the smallest file. (Using a higher bitdepth would simply waste space.)
Hmm.. Well, after noticing that the file size of an image pasted into a Lister was smaller, I then opened the images, zoomed in, and compared them. The image directly pasted into the Lister was much more pixelated/blurry than the image saved directly from Awesome Screenshot and the difference between the images seems to be the bit depth. The difference in quality when zoomed in a little is very pronounced.
Maybe there is some other contributing factor, but if not, it might be worth considering adding a bit-depth setting as an option.