[Feature Request] Option to add background color for images shown in image diff panel

[unidoc-anom]

I have a lot of files that has transparent background color which sometimes make it hard to view the diff because the content is obscured by the rectangle tile background that currently being displayed if the image is transparent.

An option to set a background color would be appreciated even for a basic and predefined color. Most of the time white background color is sufficient in my case.