GoldCamera is a photographer's (or math lover's) best friend, allowing you to change grids and line up your images in a number of ways, from a traditional 3x3 grid to the golden ratio. With centering tools, guides to help you find the centers, and numerous options, those who know how to use these grids (and those who want to take better pictures and are willing to learn) will love how accessible and quickly they load and work for your camera.
When you load GoldCamera there are up to 26 different mats to choose from, though some must be purchased in-app. For those familiar with composition, they will be very useful. For those who aren't, the app does a good job of telling you why each mat is included and how it can be used to improve certain types of photos. With topic specific mats for things like "cooking" and "baby" the results are often much better looking photos, even if you can't tell right away on the smaller screen. You can also specify the size of your photos, share to social media, and display data on the images as you take them for future reference. While not a full-blown photo editing tool, GoldCamera offers enough features that you won't find in other comparable apps that it's well worth the free download.
If you want to practice better composition in your iPhone photos, or simply explore different options for taking different types of photos, GoldCamera is a fun and free app with clear instructions and numerous modes that can lead to better photos, even for those new to the concepts it teaches.