Consider clarifying this procedure.

1. Please suggest editing picture desired to get to pixel and byte size acceptable.
2. No mention is made of what picture formats (jpg, gif, etc.) are acceptable which complicates dealing with upload failures.
3. Error message identifying why an upload failed would help.
4. When I finally actually succeded, I still received the upload failure message only to be surprised by success when I returned to one of my latest posts.

It was frustrating. I tried multiple times before succeding.