Mary, what size do you want the quilt? Make your blocks at least 8" square. This way you can see the pictures. I would do the men's Guayabera embroidery design as your sashing between each square, or something similar.This breaks up the squares and frames them like individual pictures. Cotton is the best fabric to use for quilting. You can make it monochromatic and just use your embroidery as your color. Or you can match up your colors. If you do a monochromatic, then a good muslin would work and is inexpensive and easy to work with. Remember if you are making your squares a certain size, make them larger that what you want because your embroidery will take up some of the sizing of your square. Hope this is a little helpful. Below are a couple of other designs of the Cuban Flag.Terre
Sick has although some frames to put pictures in it. maybe this will work for your quilt?
The link is to the motherday-theme but they have some more. Click on the blue link on the right site: "Search design sets only" and there on the word "frame" and you will find them.
Another little frame is on atimetostitch in the freebies in the last row; cute little rubberduck. Maybe you can use just the circle around the photo and leave the ducky away?
Sorry my spanish is much worser than my english (no word :o) so I have to ask in english: Do you look for a way to make appli frames on the quilt with plastic in front to put photos in it?
Maybe the cardhalder on digistitches can be a possibility?