I have an upload script that uploaods photo to a specific folder, I would like to input the image - title - description and credit directly into the image database.
But I cannot do this becasue when the directory is accessed it overwrites the entry I had entered.
Is there a way I can turn off the database update when the thumbnails are created?
No, you need to understand that Zenphoto is filesystem based (http://www.zenphoto.org/wp-content/uploads/2008/09/zenphoto-12-image-discovery12.jpg). It fetches what finds within the albums folder. If you want to have the info automatically fetched the easiest is to use the EXIF/IPTC meta data to attach info.
Creating the thumbnails (or any other action) will not overwrite an existing (properly created) database record. So, if your upload script does a $image = newImage(album, imagename); then populates the description, title, and credit fields, then does a $image->save();, nothing will be lost.