Image Color Analyzer is a free app which provides detailed information about the colours used in an image.
The target can be an existing file, or a new picture taken from your device camera.
Image Color Analyzer examines the colours used in your image, groups and sorts them from the most dominant to the least significant.
A report then tells you the name of the most dominant colour ("dark cerulean", say), and the other major elements, along with their percentages.
You also get the color RGB value, hex code, group information and more.
A handy free tool for photographers and artists.