Good catch! As to this (deeply stupid) behavior when a missing file is encountered, that is unfortunately inherent to the engine. As to the specific missing file, I have no idea how it got left out of the current build! Or how I didn't notice it missing in my last run of playtesting. Weirdly, on my end, it's like it never existed, it's not even in any of the backups I made, all of which I playtested, clicking on the painting (I thought) each time out of habit. Anyway, here's the missing file:
Pop this into wherever you have the game folder at on your machine/www/img/picture and it SHOULD fix the issue. Let me know. Thanks!
In other news, have you attracted the attention of the Hounds yet?