unsplash.com

Here is a short video that I made as part of my application for a "production" license for my Asset Manager plugin. This plugin allows easy access to unsplash.com images for use in ContentBox.

(unsplash.com has to approve applications that use their API in order to allow a large number of API accesses.) 

The actual plugin is a modified script I bought on codecanyon.com.  It was called "photohub."  It basically was a clone of unsplash.com, and because of that was eventually banned, I believe, from codecayon.com.

If innovastudio decides to add access to unsplash.com images, I'm sure you would integrate it directly into Asset Manager (now files.js), with no need for a separate plugin.