image-archive
Wikimedia Commons
The largest repository of freely licensed media — over 110 million files — behind Wikipedia and its sister projects. Everything is searchable on the website, and the standard MediaWiki API serves the same search without a key. Reach for it when you need openly licensed images and other media with documented sources and licensing.
Images API
Why it’s useful & how it works
Best clean keyless image API; works both ways. Set a descriptive User-Agent (WMF policy). srnamespace=6 = files.
What’s inside
110M+ freely-licensed media files.
API access
https://commons.wikimedia.org/w/api.php?action=query&list=search&srnamespace=6&format=json
Access
Programmatic API access (a key may be required — see the API tag).