Ehhh.........
Like they said: http://www.imageshack.us/
When you have uploaded you can either chose a link to the full picture, or a thumbnail.
I recommend thumbnails if your picture may not be of interest to everybody in the thread, or if you have lots of them.
Just copy the relevant link into your post, and use "preview" to verify that it looks ok.
]]>upload the picture to imageshack
]]>follow link
]]>