How to include an image in a page:

Upload it

While editing your page, add an attachment link like this:

[[Attach:myImageName.jpg]]

Then save your edits. This will make a link in the page that looks like this:

Attachment link.

Click that link and you'll get the upload screen, which looks like this:

Link to it

All uploaded documents end up the uploads folder. There are subdirectories in the uploads folder for each section of the site. Check the URL of the page you put the attachment in to get the subdirectory. For example, if the page is

http://itp.nyu.edu/physcomp/intro-pcomp-f05/Profiles/tqi6023

then the image would be in uploads/Profiles. To link to it, replace the attachment link with an image link, like so:

ThisWiki:/uploads/Profiles/myImageName.jpg

Here's an uploaded example: