The Flickr Ruby library by Maël Clérambault aims simplicity of API access. What it does is to map the methods of the official API docs. At the same time, it returns methods intuitively. This library is always updated because of the introspective features of the new methods added continuously by flickr.
Even the most modern responsive websites often struggle with selecting image resolutions that best match the various user devices. They typically have to compromise on either the image dimensions, number of images created, or even worse, just simply use a single image with the largest resolution.
You are a major brand wanting to advertise. Do you: A) hire an advertising agency and pay big bucks for photo shoots, or B) crowdsource images from your fan base for free? The Olapic API integrates answer B into other apps.