My kids have made frames for grandparents. At most any craft store or even Walmart you can buy unpainted wooden frames for less than $5. My kids have painted them with craft paints and/or decorated them with foam stickers or scrapbook stickers. You could buy two and have the boys decorate one for each other and do them together. Otherwise you can buy a frame for pretty cheap at most discount stores.
Another fun idea might be to take several pictures of them or dig up old photos and put them into a small album. It doesn't have to be anything fancy. I usually just but small ones at Target for a couple of dollars that you slip the pictures into.
Definitely take the picture with your iPad if that is easiest. I'm pretty sure that if you take your device with the cord that connects it to the computer to any Walgreens/Walmart/Target that you can connect your device to their photo print machines and print out the photo in whatever size you want.
I think it is easier to use my Canon camera. All I have to take to Target is the memory card. Stick it in the photo print machine and select the picture you want to use. You can use the touch screen on the photo machine to crop, adjust color, etc. I've never done it, but I think you can also add borders to the pictures.