I just like to add that I would like to see pdf-support too, but I wouldn't mind if I needed to create the thumbs myself. Ofcourse it would be great if sometime in the future a pdf-file could be shown on a seperate page in a seperate theme file (like pdf.php, next to album.php), but perhaps workarounds could already be made now...
Personally I would like to use pdf's as containers for ideas/concepts/layout-examples/brochures/instructions etc. I could upload the pdf files manually and also the images. From the images ZP can make thumbs, just as it does now. The PDF-files with the same name in that same folder would/should be ignored. Then the only thing needed would be a slightly different template file (lets call it pdf.php), and in it we should have just the link to the pdf-file instead of a link to the image, like this (I'm not a coder

):
`<a>getPDFLinkURL()); ?>" title="<?php echo getImageTitle();?>"><?php printImageThumb(getImageTitle()); ?></a>`
or
`<a>$_zp_current_image->name.".pdf"; ?>" title="<?php echo getImageTitle();?>"><?php printImageThumb(getImageTitle()); ?></a>`