Before applying a filter, you can crop your photo either manually or using one of the present formats.
Once you crop your photo, you can apply the filters. Although there aren't tons of filters to choose from (less than 20), there are more than enough to give your photos cool artsy effects. In fact, the goal of almost all the filters is precisely that: to make your photo look more artistic.
Ultrapop is an interesting photo-editing app with some really cool filters. The app's elegant design also makes it incredibly easy to use.
Requires Android 4.0.3 or higher