I've noticed when you attach images to talk.maemo.org threads, that they often get resized. Different images seem to get resized by different amounts, probably to do with their size in kilobytes. For a particularly messy example, see the Buddy thread.

The Manage Attachments window shows a maximum width and height of 620, plus a maximum number of kilobytes, which strangely is different for .jpeg and .jpg, and the limit for .png seems small too. Can the limits be raised, to see if that stops the system from resizing things inconsistently?

Sorry cant answer that for you.
But if i can digress (still relating to TMO) my N900 has stopped storing my credentials for TMO so everytime i visit http://talk.maemo.org im asked to pick my user name and then hit log in. It's fine on my PC.

Anyone else experienced this?