Customizing profile page?

I'm having trouble figuring out how to really customize my profile page. Specifically on how to turn images into HTTP URLs. I've tried looking it up, etc, but I can't figure it out. Would anyone be able to help me out?

You need a link of whatever picture you want to use so it has to be hosted somewhere online. By right-clicking on the image you should get the image url to use.

Does that help?

I've been able to get a proper URL, one that starts with http/https and ends in a file format, but it still says that it's not a valid URL? 

You can use postimg.cc to upload the image you want to use as an avatar and it'll give you the proper link to be able to use it here!