Let’s start with a simple description. An image manipulation library or IML is a tool that’s main goal is to help you systemize, organize and manipulate graphic elements of your app in different ways. Different image manipulation libraries typically serve different purposes and can perform such goals as cropping the images, resizing them, converting them from one format to another, improving their quality and many-many more. So, all and all, a tool to use when making a web app. Unless, of course, you want to make a dull monochrome app that contains no images whatsoever, which is an unrealistic scenario in a modern world, where design can make or break an app just as easily as its functionality or usability.