I can't link to galleries listed in artnet.com's newletter list of new galleries on their site - they choose to have people just click on the general site and then subscribe to the newsletter, to protect their image rights.
However, I just had a delightful time looking at the new gallery list in their current newletter, and recommend email subscribing to it. Each gallery will have a list of artists, many of them major and or interesting, and the photos of the individual works are good.
And those are just the newly listed galleries... the main list is quite vast and I can imaging hours of happy exporing of the work.
for more info.
Here's the specific page for subscribing to the newsletter -