When I download https://www.chessvariants.com/graphics.dir/alfaeriePNG/wking.png or wrook.png, etc., I get a 48x48 image and the white is 255.
Indeed, strange. And the GIF image of King is 49x49. All I can say is that every image I made (and I made a very large number of them) in PNG or PNG35 were rendered with the http://winboard.nl/my-cgi/fen2.cgi piece server, at a size 50x50, using its default white color, which is 249,249,249. As I recall it most of the old GIF files were also 50x50. (I am pretty sure of that, because I could not use them in WinBoard, which required 49x49 as the closest size.) The Wazir on the alfaerie GIF page is 50x50.
So I guess there is no consistency. It is the King and the Rook that have the wrong size and color, though. I should remake those one of these days.
Indeed, strange. And the GIF image of King is 49x49. All I can say is that every image I made (and I made a very large number of them) in PNG or PNG35 were rendered with the http://winboard.nl/my-cgi/fen2.cgi piece server, at a size 50x50, using its default white color, which is 249,249,249. As I recall it most of the old GIF files were also 50x50. (I am pretty sure of that, because I could not use them in WinBoard, which required 49x49 as the closest size.) The Wazir on the alfaerie GIF page is 50x50.
So I guess there is no consistency. It is the King and the Rook that have the wrong size and color, though. I should remake those one of these days.