As described here, the MapCore attachment settings were modified in March 2008. You can now post 500kb images, you get 15 of them per post, and the thumbnails are optimally sized rather than being tiny.
Below is an example of an inline attachment. It's automatically framed, it's linked to a full-size version, and it includes a caption if you define one.
[attachment=2]hl2_episode_two.jpg[/attachment]
If you attach some images but don't put them in a particular part of your post, they'll be put at the bottom as seen below. You'll probably prefer to use the inline versions so you can choose where they're displayed and in what order.