i keep getting the error: "Object reference not set to an instance of an object"
i'm slightly confused, does anyone have a solution?

Sorry you've not got any replies so far. Have you tried uploading the image using another browser (e.g. firefox instead of chrome)?

That error suggests there's an error in your html code, such as a = something blank in quotes, or a tag that doesn't have any value. Of course, it's hard because you cannot post your html in order for us to review it as that would, well, pump it into your reply and give you an error ^^; 

Here's a link of step-by-step to produce a sig. Try following it?
https://www.royalroad.com/forums/thread/107061

There's a couple of other methods (well essentially the same but explained differently) in this thread too.

https://www.royalroad.com/forums/thread/107460

Hopefully one of them will help!

If not, relaunch the help plea. Do you have a hosting site for your picture, such as flickr or tumblr? If you do, try taking a photo of your sig code and then posting that picture in your hosting site, and then inserting that pic into your thread so people can look at your code and debug it. God help me, there's probably an easier way of showing us your code, but I can't figure it out...

Mal Wrote: That error suggests there's an error in your html code

They said 'temporary cover image' in the title, so their problem might not be HTML related. OP, if I'm wrong you can post HTML in the forums by using the 'Code' button. It'll look like this: