JSTOR Images - thousands of images/art work contributed by partnering institutions like universities, museums, community and private collections from around the world.
RIBApix - over 100,000 digital images from the collections of the British Architectural Library. Registered users may freely download low resolution images with a small watermark on one corner for educational uses such as essays and dissertations provided that each image is fully credited.
VADS - over 140,000 images from over 300 art and design collections across the UK. Freely available for non-commercial use in education.
Access from the Photography subject resource list