You said your image files are being uploaded correctly, and the first example you cite (picture of a VW beetle) shows a correct full-size image and a "truncated" thumbnail. But then in one of your sub-replies, you cited another web page with bad thumbnails, and when I followed one of those through to a full-size image, that full-size image had the same symptom as the thumbnail -- the lower few scan lines were solid grey instead of being the photograph.

Compare any of the thumbnails here against the full size image that is shown when you click on the thumbnail: http://mtziontrenton.com/cgi-bin/ezwebalbum.cgi?cgiAction=albumDisplay&category=Celebrations&album=Celebrations2

If you're creating the full-size image by expanding the thumbnail, then ignore this reply. (But why would you do that?)

Otherwise, recheck your process for uploading the images -- my guess would be there's a "dos text-mode" component somewhere in the transfer, and the image files tend to have a byte somewhere that equates to ^Z (EOF tag for dos text files), or else there's just a ^J ("new-line" in text files) where a text-mode transfer is prepending ^M ("carriage-return"), and that's screwing up the image stream. But that's just a guess.