need "invisible" user account-Thesis

Hi, I’m in WordPress Thesis and will ask there too but am starting here. I have a site with user accounts where the members are all artists and have art and a profile on the site. When I create an account, I need to add an art thumbnail, then that user shows up on the home page gallery.

Problem is, a few members choose not to have their art and profile on the site. They still need log-ins though, so they can see the private member announcement area. If I create a user account with no art, it messes up the look of the home page–instead of an art thumbnail you see their name and a thin gray rectangle. If anyone can give me some advice, or is a PHP person who can fix this issue for pay, please reply. I can describe which plugins were used. Asking the plugin creators won’t work (tried that with other questions).

Thanks!