Dutch site http://www.geheugenvannederland.nl/ has a series of very fine quality photos from mostly WW1 for tank related stuff. I won't reproduce them here as many appear elsewhere although some are better quality than I've seen before like these http://i.imgur.com/g0ibpQe.png http://i.imgur.com/g0ibpQe.png http://i.imgur.com/XERXrmz.png
The ones I've not seen before which are hopefully of interest:
Obviously go to the site and use 'tank' to search and you can find them in higher resolution
