This is actually a bit different from the highlighting trick. This isn't using selection mode to hide or reveal anything; it's more about making a mockery of most imaging software.
It's not related to the IE selection bug/feature. It's a bug in gamma calculations performed by image scaling algorithms. See the link just above your post for details.
this is like a double suprise.1st the thumbnail has satori with diamond background, but when you click the image you get square background. and if you resize it, you get another suprise....
This looks pretty neat when you right click it and choose "view image info" in Firefox. It goes from gray background to the full picture with a sort of checkerboard transition.
All I know is that the background of this image has a sense of very fine static, like it has been animated. I don't know whether that's the browser or my eyes. It's also flashing inverted colors temporarily as I scroll (I know that's the browser). I don't know which effect is more unnerving.
I opened http://danbooru.me/data/19e348d961a2338bcdff7dc9abd92723.jpg on Internet Explorer and had quite ghastly experience as I saw what appeared to be opaque picture of Koishi on that checker-boarded grey-dark grey background for few seconds until it vanished as image re-sized.