Add icons to indicate filtered images

[rowink]

Is your feature request related to a problem? Please describe.

Currently, it seems that it is not possible to effectively recognize filtered images, and there are potential error filtering problems if strictness is too high.

Describe the solution you'd like

Add an icon to indicate display next to the image

With this solution, it can also expand some other operations, like switching image display.

Describe alternatives you've considered

I observed the filtering of the image was implemented in style, my current idea is use pseudo classes to add an identifier to the image. then set the click function for it.

Additional context

Or add an button to indicate similar to Double-click Image Downloader.

[rowink]

Grayscale is soft, but it will not be able to identify gray pictures.

[heliomar-pena]

It sounds like a good feature, I think it could be configurable by the extension panel so users could disable it if didn't like