Add Example with Numbered Tiles

[strawstack]

Hey, awesome tool. I'm new to making tile maps, and I've been having a hard time figuring out which tiles in the input images represent what tiles in the preview image. I made an input image where I drew a number on each tile, and I could clearly see which tile was which in the preview image. I would request that such an example input image be added to the examples, or wired up so that new users could quickly understand what tiles in the input image map to what tiles in the preview. I've included an example image, but a better version would be the existing brick tile input but with numbers or letters on each tile drawn on them.