I have a gallery of photos arranged in separate albums and I want to have cartoon icons as the album thumbnails instead of one of the photos.
I have uploaded the icons, one for each album, and made it the selected album thumbnail for that album.
But it also displays as one of the images in the the album as well, not just as the album thumb.
Is the anyway of 'unpublishing' a single image so that you can select it as an album thumb but NOT have it display as one of the images inside the album.

Yes, it is possible to set an image unpublished (we call it "not visible") and then choose it as an album thumb. Note that while you are logged in you will see even unpublished images and albums.

Excellent. It worked.
I was still logged in so I was wondering why setting 'not visible' didn't seem to work.
Thank you for a fast response.