The best source of paintings on the Web, thousands of thumbnails sorted by artist, by country and by time period, linking to good-quality scans. All paintings are given title, year and technique. There is a featured artist section which gives a good overview of a surprising number of artists, with biography sections too. The pages are nicely set out and download time is reasonably fast, given the number of thumbnails
Another excellent site, Brian has chosen to feature his own personal favourite artists, many of whom are quite obscure, including Maxfield Parrish, de Tadema and the like. There are scores of good quality scans and some biographical material, plus many useful links to other resources.
A positive overdose of romantic paintings, from Rossetti, Lord Leighton and the like. Well presented with some good quality images found smaller or grainier elsewhere. Some info provided, plus a bulletin board service for lovers of Pre-Raphaelite art. If this is your thing, go to it!
A comprehensive resource of links to almost every aspect of art you could think of, from ancient times right up to date. Chris Witcombe has done a pretty good job though you may find yourself frustrated when searching for more obscure works by a specific artist... A good starting point.
This site is wonderul to look at before you even start on the art, a very clear layout which is easy on the eye and easier to navigate. Not only the main gallery collections are here but lists of artists works, biographies and a variety of articles discussing individual paintings in depth. This is what the Web was designed for!
Anyone who has tried looking for Russian art outside the mainstream will be pleased to find this site, which has a good number of links, I hope they will add more as time goes by.