Gimp is also a good software alternative if you can 't afford photoshop.
It's a free utility and easy to use. The only thing it can't do is work with animated gifs. You need
Photoshop for that.
My suggestion is go to google and look up sig tutorials
Pro-tip: you use already made backgrounds if your having trouble making one from scratch.
Just change it up and blend it in with you're sig.
Pro-tip: if your not found of rendering you can always search for png images which are per-rendered already.
Good luck any questions you ask me.