You do not even have to register and it is fast, with the link options available for reposting, clearly marked.
You have some control over the size of the image to be displayed and can edit and crop before you upload. Most of the images I have posted on the forum are hosted there - the link under the heading BBCode (message boards & forums) works on the forum (but there are others too).
You can use the upload button on the website or upload directly from a website or your pc by downloading some free tools. For that (and some more free functionality) you do have to register.