A free app for Android, by Developer 360.

How to use:

FotoRus has an easy-to-use interface. First, you can choose the desired mirroring effect and then select your images. Next, you can apply filters and photo effects. The editing process is quite simple, and you can do everything you need in a very simple way.

The most important, FotoRus has a powerful photo editing tool. You can easily combine several pictures into one collage photo frame and grid. 

Photo collage editor

Select your desired collage maker to combine several images into one frame. You can choose from a wide range of collage layouts. Besides, you can add filters, stickers, text, etc.