My bad (well, the forum's technically). The default setting for viewing attachments was off for mods. Dumb. I'm sure we'll continue to uncover little quirks like that for the first few weeks.
Racefla - nope, you did it just right. If you upload pics directly to the forum as attachments, they get stored locally and show up as thumbnails. Clicking on them expands them to full size, clicking again shrinks them back to thumbnails. If you link to pics already hosted somewhere else (as my original pics were) by surrounding the url with IMG tags, they show up as full size inside the post itself. Either way is fine. If they are already hosted somewhere in a personal gallery, you can simply link to them. If they are just on your pc, just upload them as attachments (which, btw, is in the "Additional Options" tab below the textbox for those that haven't found it).