Hi, my client accidently uploaded a mac desktop thumb file inside a zip with some images. Although I'm not sure if this is the reason but now I can't get rid of these "missing image" icons (see url below). I've deleted the album....deleted the folders and re-uploaded...at first they go away but mysteriously start reappearing.

Any Ideas how I can get rid of them?

http://www.nomadsurfers.it/surfgalleries/california-61/

Yes, that can be the reason, these files can confuse zenphoto. Did you refresh the database?
Also, these images seems to have a css class "not_visible" attached. Is that supposed to be? The others in the Santa Barbara Surfcamp album don't have that.

Yes when you flush the database they go away...but for some reason, one by one they start appearing again...very strange...can i delete references to them directly in the database? What would i look for?

As for the css class not visible, I have no idea where that came from...it wasn't me.