This blog's most recent post about 'Top eBay Chess Items', The Kitten Theme, featured a painting by Gerard Portielje (Belgian, 1856-1929) and noted,
A search on 'chess Portielje' brings up two other works by the same artist.
Afterwards I noticed another painting and started to wonder how many different chess paintings there are by Portielje. Using the following image as a starting point...
Google image search on 'chess Portielje'
...I numbered the rows from top to bottom as 1 to 3 with the paintings from left to right in each row identified as A, B, etc.. The 'Kitten Theme' painting (first row, second from the left) is thereby identified as 1B.
That identification scheme reveals the following pairs of chess paintings: 1A & 1C are the same, 1D & 2B ditto (although certain details like the cabinet on the right of the painting are not identical), 1E & 1F ditto; plus two unpaired paintings: 2A and 2F.
2C and 3C show the same painting, but it's not a chess scene. The other Google images are either not by Portielje or not about chess.
That makes six different paintings on the first Google search page. I found a seventh on the second search page, which leads to valsur 274753.html - Valerij SURKOV, showing four Portielje images (among many others by other artists): 1A/1C, 1D, 2B, plus the new painting.
I wouldn't be surprised to find more.
Later: I found a second Valerij SURKOV collection of chess paintings: valsur 337769.html - Valerij SURKOV. This page also has four Portielje images -- 2A, *, 1E/1F, and 2F -- where '*' is a painting not identified above. Change the title of this post to 'Eight Portieljes'!
I also searched my collection of ~10.000 chess images (most of them from eBay) for Portielje. In addition to 'Kitten Theme' (1B), I found several variations of 1E/1F, the best of which had the accompanying text:-
The title is 'The Chess Players'. This print was issued by the Denver Post, December 7, 1902 (printed in the lower left corner). [...] This was printed by the American Colortype Company as a supplement to the Denver Post newspaper.
Another variation mentioned, 'Originally this print appeared as a supplement to the CHICAGO TRIBUNE on 2/2/1902'.