Recently I saw a few IGers posted photos with a circle frame. I’ve never used it to frame my photos so I started to look around. I found a few apps (Roundgraphy, tadaa, and Super Retro) that are quite decent but Diptic ($0.99) has to be the better one as far as the adjustability is concerned. Diptic is essentially designed for a layout of two and more photos but you can also use it for one single picture (4th screen of the app). Use the “Border” on the “Effects” page and turn on “Rounded Inside” and make it 100% . You can also adjust the color of the area outside the circle frame too.