Yup, you gotta find somewhere to host it. A few guys on here might be able to help you out with that. Or google search from picture hosting sites.
A few posted in here
OR
You can attach a file (bottom of reply box). There's a max size the pic can be in order to attach it tho...not sure wat it is. So just shrink it with an imaging program so it'll fit.
THEN
Use the tag up there ^^ and copy the address of the picture into the box that pops up (right click, properties, copy url, paste url into box).
Don't hesitate to msg if you running into problems :D