The Pixabay PHP SDK by Philipp allows API communication to implement image search features into applications. Usage example shows code to access the API with username and key. Code also demonstrates how to test the wrapper to obtain results.
Instagram is one of those early adopter favorites that quickly crossed the chasm to more mainstream users, at least within my social network. Take that popularity, mix it with an apparent desire to buy shirts, and it was inevitable that someone would use the Instagram API to create wearable mashups. In fact, there are at least three such services, each with its own twist.