An interesting twist on the picross genre by fusing it with an art collab! Usually I would think that the art collab part would involve the finished picture in the end being something someone drew, but the idea to have the art pieces be found within the filled parts of the board was quite unique. For the most part, the game works well and provides some decent picross fun while allowing you to see some cool artwork (and the artists behind them as well!)
There are some awkward aspects to it, though. Because the artwork shows up for filled spaces immediately when you complete a row, it allows you to 'cheat' the usual Picross rules by just brute-force filling in rows until you see art pop-up: usually you don't get that type of confirmation until the very end, so this is a lot easier than typical Picross. Furthermore, it feels like the usual thrill of a Picross game, where you want to see the end result, is gone because it's second fiddle to seeing the tons of art within the tiles. Viewing the art is also a bit odd: when you click on it you can zoom-in, but only on the center and not anywhere else, why no dragging or scrolling? Also in general I wish the game had a bit more pizazz to it, like special effects or sounds for filling a row or completing a puzzle: felt pretty dry without it, just listening to the same music over and over. Because of these issues, I did feel like I found myself not getting too addicted to this as I usually would for other Picross games.
Despite my complaints, I still think the idea is pretty neat and there is a fun game here, so kudos on the rather special way you choose to have this art collab: certainly more creative and unique than your typical gallery!