I think, if you attach images, over a certain size, they automatically become thumbnailed. However, at the moment, I have attachments limited to 5 per post. It seems like a reasonable number, for support type messages. But there's no way to have attachments limited by board. So for example, I can't have unlimited attachments for some boards, and limited on others.
But doesn't OCA provide thumbnail codes, so you can automatically embed thumbnails? I know a lot of image hosts do (such at ImageShack). Or maybe there's a bbcode for thumbnails. I'll look it up...... Hhmm, no there doesn't seem to be such a code....too bad. I guess SMF must be depending on image hosts to provide thumbs.
OR, you could upload to your gallery. There, thumbnails are automatically created, and then just embed that thumbnail. It actually makes 2 different sizes of thumbnails automatically. 1 is the tiny thumbnail, that you see in the album view, and the other is the image you see on the "intermediate" page, the one with all the image info. However, if the image isn't any bigger than that size, it doesn't create the 2nd one.
Although I guess you've reached your limit for the gallery. Maybe now that you've graduated, you don't need all those images related to your thesis anymore?