No, it's legit. Arty's the real deal :)

It's based on Marco Sodano's "Lego Masters" series from around 10 years ago (before AI filters), and is done with surprisingly basic tools inside of Photoshop. You can try it yourself:

Let's start with this photo.

1. First up, we need to find a good image of a Lego brick. In order to match the look of the original, we can just isolate one from a high-res version of a Marco original.

Take that brick, tile it into a similar-sized grid that matches the aspect ratio of your source photo. Like so. Make sure to desaturate it, and keep the average brightness around 50%.

2. Next, take your source photo and go to Filter > Pixelate > Mosaic and set the grid to match your bricks.

3. Put the bricks layer over the pixelated photo, and set the transfer mode to "Overlay".

You'll probably need to mess with the brightness and contrast of both layers to get the colours to look the way you want.

You can also pop-in the Lego logo and "IMAGINE" brick to mimic the original art pieces.

If you really want to go the extra mile, swap-out some of the 1-piece bricks for 2, 4, or 6 piece bricks (if you find clusters of similar enough colour in your pixelated image).