I'm not sure. Do you use the insert image tool? I just used it to test it and see if it works. But, no matter how big the picture is, He is such a little cutie!! Love him!!
When you use the FBN upload tool, it will post a thumbnail (clickable). However, you can post the full size image easily. After you post, click on your thumbnail to make it bigger, and the RIGHT CLICK, and copy the URL.
Using the insert image tool, choose From URL instead of From Computer. Uncheck the 'retrieve remote file and reference locally' box. Then you will have a full size image.
Also if you create user albums, there is codes you can share on the forum (just click on the photo to see them) of those pictures.
Uploader tool or insert image are the same, sorry. The manage attachments (when creating a new post) is a little different. I do not use that one, unless I am editing something.