Hi Marc,
There are various ways but I use Photobucket. If you have an account you will know what to do. If not -
open a free account
create an album
upload pics to your album
view the pic you want to post
on the right there are options to post the pic
click on the IMG code (auto copies)
paste the link here (or where ever).
It sounds difficult but after you have done it twice it will be easy.
Hope this helps,
Richard