Requested feature overview description.

An indicator of sorts on thumbnails to indicate whether a user has voted on or favourited a post before clicking on it. Something simple like changing one of the border colors (not the entire border because that would interfere with other border colorations) or text in the stat bar should work.

Why would it be useful?

Sometimes, a user would find an interesting thumbnail while browsing and decide to click on it and see if it's worth voting on or favouriting only to find they've already done so. This will help avoid some unnecessary clicks.

What part(s) of the site page(s) are affected?

https://e621.net/post/index/, and maybe other pages with thumbnails depending on how this is implemented.

How about this.

↓1 ♥1 C0 E U

Voted up:

↓1* ♥1 C0 E U

or

↓1* ♥1 C0 E U

Voted down:

↓1* ♥1 C0 E U

or

↓1* ♥1 C0 E U

Favorited:

↓1 ♥1* C0 E U

Voted up and favorited:

↓1* ♥1* C0 E U

or

↓1* ♥1* C0 E U

The green asterisk is hard to distinguish from red so default color and black could be used.

That can work. The green and red are distinguishable enough to me, but having the option to change it to black and white wouldn't hurt.