It's funny. As the cameras in our iPhones get more spectacular capabilities, more apps are appearing every day to give those beautiful high-resolution photos scratches, tints, and frames that make them look ... well, not so nice.
Analog (Realmac Software, US$7.99 introductory price) is another Mac app that lets you change the look of your photos with an assortment of filters and borders. Others that you might want to check out before you make your choice are Flare ($9.99 through the Mac App Store right now or $19.95 on the Iconfactory website) and FX Photo Studio ($9.99).
All of these apps pretty much do the same thing. You open a photo file or drop it onto the app, and you're presented with a number of preset filters that change texture, blur, saturation, brightness, contrast and tint. There are probably more settings, but I'm just picking a few. Why would you want to do this to a nice, clear digital photo? A lot of photos look good, but seem to lack emotional impact. Adding an effect to a photo often brings back that impact, by reminding people of photos from the past or by adding dramatic coloration.