What is the image aspect ratio?
The aspect ratio is the proportional relationship between an image’s width and height. Different cameras shoot in different aspect ratios, so whether you’re using a digital camera, a 35 mm film camera or an iPhone, they can all vary. Understanding the image size and ratio is important because it affects how you compose your shot and what the print size will be.
Note that the aspect ratio of an image refers to its dimensional ratio but not the actual resolution or total pixels the image contains. A square 1:1 shot could be 500 x 500 pixels or it could be 2500 x 2500 pixels.