[@Nightknight]
Find a site to upload your images to and link to that. I prefer Flickr, since you can downsize large images however you want and link directly to whatever size image you pick. Other uploading sites, to my knowledge, don't let you do that.

EDIT: You can also use [url=http://www.picresize.com/]PicResize[/url], but it's really finnicky and doesn't always register images as valid images. The connection isn't secure either, so use it at your own risk.