Now we’ve got the copyright issues out of the way I thought I’d cover some other problems.
Firstly the search function appears to have issues. Searching for “HMS” (a standard way to find pics of warships) only produces 21 results all starting with “A” which is a little odd (it is possible to get this a bit higher through messing with the URL but still limited). It would appear that there is an upper limit on the number of results the search function is prepared to produce. Odd
Secondly their tagging system is a little odd. Like many collections they invite members of the public to tag their images which is all well and good. In theory it makes them a lot more searchable. Unfortunately rather than allowing people to chose which paintings they wish to tag (which will presumably include those they know something about) the system forces them to try and tag a series of apparently randomly selected paintings. This means that even the most widely read person is going to spend a lot of time looking at paintings they know nothing about. The system also seems to have issues with tags of more than one word which is a problem if you want to tag a painting with say “model boats”.
Another concern is the fairly low resolution being used. At less than 1000 pixels per side the images are low resolution by any reasonable standard (exception the case of some miniatures). To some extent I suspect this is simply an attempt to keep the galleries onside. It is certainly not a technical limitation. This image breaks the 1000 pixels barrier even though the original is only a couple of inches across and the image was shot through glass.
However this resolution is far to low to do any real study of the paintings in most cases. The other concern is that since in may cases these are the only scans of the paintings in existence they provide only limited cover in case of the original being lost (which does happen). I can only hope there are higher resolution versions in storage somewhere.