So I am a huge fan of tikz (still a bit of a noob to be honest). I find that adding graphics can be helpful for a lot of problems, but I am wondering if hosting pictures in imgur is a good idea, as they could potentially dissapear. What are your thoughts on this?
While editing a post, there is a button at the top of the editing pane:
This button can be used to add images to a post. When you click on that button, it opens up a dialog which asks you to provide the URL of an image, or to upload an image. If you upload an image, it will be uploaded to imgur, then embedded here. As Math SE incorporates imgur uploading right into its interface, you are fine to use it for hosting images—there is good reason to believe that the images will persist at least as long as the SE network exists.
Indeed, SE has a deal with imgur to provide hosting services. More details can be found on the Overflow. Note that both of these links are about a decade old, but nothing significant has changed in the meantime.