[KW802]

1) Wouldn't work because the thumbnails are based upon the file extension. If you leave the extension to be a zip file then the default .zip file icon will be displayed. If you change the extension to be .jpg then it will fail during the upload process because the code checks the file extension versus the file type (as identified by the PHP function) and rejects it if they don't match. You would have to hack around the extension check.

2) Again, it depends upon much PHP 'know-how' you have and/or are willing to hack the code.