CSS Make Stylus use local files?

[KittenKatja]

Hey there,

I come back with another problem.
I am using Stylus for a while now and restructured and changed the code for the Youtube CSS and added a background picture.
Here's the problem, my current internet connection is very slow and I'd like to load the picture faster without slowing down youtube performance, but I can't find a way for Stylus to use local files like put it on my desktop, access it from its own extension folder or anything.
I have looked around for a Stylus Forum, but I could only find a changelog website with a comment section.
The following URLs don't work:
url(file:///C:/Users/<redacted>/Desktop/<picture>)
url(file:///C:/Users/<redacted>/AppData/Local/Google/Chrome/User%20Data/Default/Extensions/clngdbkpkpeebahjckkjfobafhncgmne/katja/<picture>)
url(file:///C:/Users/<redacted>/AppData/Local/Google/Chrome/User%20Data/Default/Extensions/clngdbkpkpeebahjckkjfobafhncgmne/1.5.21_0/katja/<picture>)
url(chrome-extension://clngdbkpkpeebahjckkjfobafhncgmne/katja/<picture>)
url(chrome-extension://clngdbkpkpeebahjckkjfobafhncgmne/assets/<picture>)
url(chrome-extension://clngdbkpkpeebahjckkjfobafhncgmne/assets/images/<picture>)
Weirdly enough the last is also used by Stylus to access another extensions' gif picture to replace the scrubber, I put the same picture into that folder and it still doesn't work.

 

[nya nya]

Hi, I made an account just for this!

Happened to stumble upon your post as I was searching for a solution for the same problem.
I guess you have already figured it out as I'm replying almost 2 years later,
but I thought my input would help anyone who happens to find themselves here like I did.
Nevertheless, my solution was converting the image to base64 and having it inline in the css.
Imo quite hacky but it works!

Guide here:
Data URIs | CSS-Tricks

Oh, and for some reason it just straight up doesn't work with UserCSS themes.
With non UC themes it still throws an error for me but functions normally otherwise.

I hope this was helpful to anyone reading! <3