I've never gotten the message that says upload has failed but here is what I do.
1) Take a picture of what I want to post with my camera & save it to "pictures" in my computer.
2) Start your new thread & type in what message you want to say then scroll down to where it says
"additional options" and click on "Manage Attachments".
3) Click on the "Browse" box & find your the picture you want to post in your "pictures" section on
your computer.
4) Double click on your picture & it will send a link to the browse box
5) When you see the link, click the blue upload box ---it will say "uploading file, please wait"
6) When the file is uploaded simple "x" out of that screen & it will be attached to your post.
7) You won't actually see the picture until you actually submit your new thread.
I hope this helps you.