yes you can add screenshots
type {{files}} in the page you want to upload screens to
save the page and then you get a little file upload box
use the upload box to upload the files you want
remove {{files}} from the page to make the upload box disappear (your uploaded files stay where they are)
to make the images appear use this kind of code:
{{image src="images/ThePageName/the_file_name.gif" alt="ALT TEXT" title="TITLE TEXT" link="LINK URL"}}
ThePageName is the page where you uploaded the files (normally the same page you are editing)
ALT TEXT and TITLE TEXT should describe what the image is
link="LINK URL" is optional - it creates a link from the image
Test it out in the
SandBox