Enlarged photos are key to presenting in a good gallery, try to publish your work thoroughly enough that you have at least 3 or 4 best paintings and a few others to back it up. Don't use a slideshow if I were you I think its better to just put it in a binder. There is another trick to doing it.... if you just place your best photos scattered throughout the binder take the best one and put it in the back ....if you know what I mean they definitely look for presentation skills! Try taking the photos of your paintings in the sunlight for "best exposure", it is not the color necessarily that comes through but the details of getting towards your goal of putting it in a gallery. Always use the paint on the edges of your paintings to come through in the pictures, very important!