Omeka supports various types of items. In fact you can upload almost anything, if it is listed as allowed file extenstion in Omeka Admin panel. This can be found in security settings (Settings -> Security in the admin panel).
There are two things you should know:
-
Make sure that user is able to view your content - use popular formats which are widely supported by web browsers.
-
Avoid linking between files. Omeka changes file names on upload, so if you will have two files which are linked (e.g. HTML file and an image) most probably the link will be broken after upload to Omeka. There are ways to get this solved, but they are not convenient and not recommended.