Pixlr Express is a mobile and tablet application that allows to edit images in an easier way. Includes many effects ready to use, also you can add and customize overlays and borders.
Users can resize or crop/cut parts from pictures, apply custom backgrounds choosing from different textures and shapes, create slideshows.
Also includes an auto fix option that automatically adjust all aspects of an image to repair and adjust all colors, luminosity and contrast.
Adjust spacing, roundness, proportions, use different layouts for slideshows.
You can use pictures saved on local device, just taken with webcam or camera or even from a web address.
Allows you to share images on social profiles.
Pixlr Express is oriented to photo editing and basic modifications, while Pixlr-o-matic (from the same author) is focused on filters and effects. Is not an obvious difference between these 2 apps, but you can try them both (are free) and you one that you are the most comfortable. Both are good alternatives for Instagram.