Specify different banner images between light and dark mode

[5ouma]

Summary

I want to set different images depending on the appearance mode for these.

• User banner image
• Server banner image
• Server background image

Purpose

I like to set white images to them, but it flashes my eyes when the system is in dark mode. It's the same idea with themes.

Do you want to implement this feature yourself?

• [ ] Yes, I will implement this by myself and send a pull request