PhotoScape X for Mac is a photo viewing and editing tool for Mac that provides many of the same tools as iPhoto, but in a separate interface that was often faster in our tests than the native app. While not as feature rich or as integrated with OS X as Apple's native photo viewer, PhotoScape X offers a suite of tools that makes photo viewing much easier.
Installation of PhotoScape X took only a few moments and the app loaded immediately. After setting the theme and switching to the photo viewer, the app was able to load all of the images on our test computer in just under three seconds, scanning the entire hard drive and pulling more than 800 photos into a single view, quickly. Clicking on any of these images, we could immediately apply edits and then save the file back to the hard drive in the same location or separately. The interface here is very much like a file viewer, so it's not pretty, but it's very functional and the themes add a bit of flavor to what would be a bland app, otherwise. The performance here is fantastic, though, and while additional features like social integration are missing, the app is a very solid replacement for your native photo viewing app.
PhotoScape X is a free app that works very well to replace iPhoto or any other photo viewing apps you are currently using. It's fast, responsive, and has added tools like GIF creation that help it stand out against the competition; and with no upgrade fee needed down the line, it's a very good app that could make itself at home on any newer Macs.