GridPic allows you to take multiple pictures that form a grid, in the easiest way: simply start shooting, and GridPic keeps expanding the grid (in a spiral fashion), allowing any size grids like 2×2, 2×3, 3×3, 3×4 etc, with no limit (yes, 10×10 and beyond is possible!).
Take pictures as quick as you can press the shutter! Its streamlined interface gives you a direct view on what the end result will look like, as you take pictures.
Then save to the camera roll, from where you can share it easily. Other quick buttons for restarting from scratch, or stepping back one picture to retake it.
The setting button gives access to settings for flash on/off or auto (default), the border thickness and color (default black), and whether to take pictures in spiral fashion (default) or panoramic mode (left to right).
Review on ePHOTOzine
There really is no limit to the amount of pictures you can put into one grid. To that end, the app employs a simple scheme that reduces the size of pictures by half at certain points to avoid your phone running out of memory. All grids up to 5×5 are made with individual pictures of 720×720 each. Then up to 10×10 it's 360×360, and after that 180×180. Future versions may have settings for this.
I was inspired to make this app, because I love making giant composite grid pictures (see Photography) and I couldn't find an app that would allow more than 3×3, and take the pictures quickly and easily.