A free program for Android, by Button SoftwareInc.
The Mixoo Collage app combines one or more photos into one beautiful artwork. There are hundreds of collage layouts, from simple to complex, and with various themes. It’s easy to use, with simple steps and an intuitive interface. Just select the photos you want to use, choose the layout you like, and save your collage to your device or share it with friends on social networks like Facebook, Instagram, Twitter, and others.
The Mixoo Collage app includes many photo editing tools like filters, stickers, background colors, text, and other effects. You can also use the app as an editor to customize your collages with your own photos, text, and other decorations.