Make it small, though large enough to still get the point. You can always have a link to a larger version. For line-art, make a GIF with 8 levels of gray, and compare with a JPEG to see what gives the best results. Then build a web page with a small amount of text or caption and the image. You can have clicking on the image show a larger one, and have links to your other stuff.
E-mail a joke submission with the URL on a line by itself and any prompting text.
We'll look at it. If you have a fast web server that can take the load, we'll put it there. If you ask really, really nicely we may put it up on our server. And make sure it's really funny. The moderator also has the right to make edits which, in the moderator's sole opinion, improve the joke.