While I've not tried this myself, I believe the web browsing app iCab Mobile ($1.99, USD) will aid you in uploading pictures to the web. At least, that's what others recommend.
Or, get a free online photo management, such as Photobucket, and maybe that will let you post pictures? Again, I've not tried to use Photobucket for Craigslist adsd (although I do use it to post pictures here).
Maybe these two suggestions will get you started on a solution. Good luck and let us know how you get on.
Marilyn