some more editing here, but that's fine for me,
Idea on the matter, if you want to consider:
1. having a table for attachmenttype, just like
vB's attachmenttype table, where you can add different type, specify limit for each type, specify MIME type for each type, and thumbnail for them. These can be manage (add/delete/change) in admincp
2. or search for ext.gif in some extension folder (say pdf.gif, zip.gif)
just thru out ideas
