With the common clone method for creating levels, you can only use pixels with a size of 24 X 24, but with this method you can theoretically use infinitely small pixels. (however, scrach will start to glich if you use sizes smaller than 8 X 8). When you use a sice which isn't 50 there can be gaps but this is because of the costumes you can change them when you want click to destroy.
Please give credits, if you use it. I've used some parts of griffpatchs turtorial video.