Thumbnail File change/added for the file extention?

[jonnyo]

ok i have many .zip files uploaded to my 4images site.
the Thing is, when you are browsing the catagories you can see the Thumbnail File (.jpg)
but once you click on the Thumbnail you get a picture that say its a .zip.

what i would like to know, is there a mod out there so that so that the thumbnail of the pic show's up next to or insted of the .zip file
like:
<--Thumbnail here

if anyone has any information, that would be great,

thanks jonnyo