Joomla - Phoca Gallery (modification)

Hi guys, We need a simple modification on Phoca Gallery extension we have installed on our JOOMLA 2.5 website. We want different thumbnails for the images on the website. The phoca gallery extension automatically generates thumbnails for the images you upload into an album, what we want is to have the way to upload thumbnails and different images, so when you click on a thumbnail it should open a new image in the lightbox and not the same image as the thumbnail.. The phoca gallery extension has this feature working for youtube videos but we need the same thing for the photos. That's a very simple task for someone that knows PHP well, so we are willing to pay $30 for this one, if all goes well we'll be sending more projects to the right candidate. We need it done for today or at least tomorrow, so please don't prospect if you don't have time or knowledge to do this project. Send private message please. Cheers,