Pattern in Islamic Art is an online archive of over 5,000 beautiful Islamic patterns. Images sortable by museum, monument, region, town, materials used (ceramic tiles, plasterwork, wood, etc.), or by architectural feature (decorative panel, doors & doorways, lattice-work, etc.) Excellent images and documentation.
Images are also available in prints.
The image above is from Pattern in Islamic Art:
Grand Mosquée de Paris
This mosque was founded in 1926 and built in recognition of the 100,000 Muslim soldiers from French colonies who gave their lives during World War I. Designed in a Neo-Mudejar style, with contributions from both Morocco and Algeria.