Photo Squarer effectively adds borders to your photos, but it doesn't do much else. There are no real editing features and the borders aren't nearly customizable enough. There are already great photo editors on Android that do everything this app can do and so much more, which makes this app hard to recommend.
Photo Squarer adds narrow borders on any side of your photo to turn the picture into a perfect square. The app won't resize the actual content of the photo into a square, though. It won't let you add any designs or other goodies to the borders; you can just change the color. You aren't able to edit the photo in addition to adding the border, either. There's no way to crop, filter, or resize the photo from inside of Photo Squarer, which drastically reduces its usefulness. You can only save it or share from inside of the app. What's nice about it is that it makes photos compatible with Instagram.
There's not much going for this app just because there isn't very much this app can do. If you really need your pictures to be perfect squares, this is an easy way to do it. However, don't expect to get much else out of Photo Squarer.