I took a look at FX Photo Studio on the iPad earlier this year and gave it a positive review. Now the app has migrated to the Mac App Store, so that users who want to work on a desktop or laptop Mac can modify, adjust and remake their images using similar tools to the iOS versions. I've been using FX Photo Studio Pro for about a week and imported many of my images to see how it worked. The app is no substitute for Photoshop, but for the casual photographer who wants to explore filters, do basic sharpening, level adjustments, color balance, crop, rotate and change the color saturation of images, I think the app is worthwhile.
With 159 filters, you can dramatically change your image. As with all filters, you are more likely to mess the image up rather than improve it, but if you are after a big collection of effects, you'll find them here. I thought the black and white conversion was nice and clean, and some of the vignette effects were also good. Things like night vision effects and some color glows that look like LSD-induced nightmares aren't my cup of tea, but some people will love them. That's the strength of having lots of filters. Use what you want and forget the rest. You can also create your own variations on the filters and save them for re-use. Images can be shared from within the app via Twitter, Facebook, email, Tumblr and Flickr.
The app has a handy split screen mode, so you can see before and after your changes, and of course, there is undo.