If you want to post it as part of a message- you'll have to host it somewhere online. This is not hard- basically you upload the pic to a site somewhere in cyberspace so it is always available for someone to look at. I like photobucket (
www.photobucket.com) for this sort of thing, it's very user friendly, it's free and easy to link to once you get the pics uploaded to their site.
If you want to post it as your avatar (small pic that shows up below your name) then I think you'll need to resize the pic to make it below 8mb.
Let me know if you need help- I'm not an expert, but I've done enough of this that I should be able to lend a hand.
Bret.