Jakob said: This is a bad idea, because roll20 will end up super-slow to unusable if you put 3700 background tiles on the same map. Instead, download the tile, repeat it in Photoshop/Gimp, and then re-upload it (roll20 will still dislike you for using a 250 by 250 map, but less so than if you fill it with tiles). Hundreds of tiles would be too much, I agree. Photoshop method is a good approach here. However, alternatively, filling a page as large as 250x250 with tiles or maps of 50x50 would be much better than with tiles of 4x4. I've had the best success making individual tiles no larger than 5500x5500 pixels (which is around 78x78 units), but having several of these adjacent on one Page has not been a problem on any of the computers in my game group.