This question is similar to How can I convert an image's pixels to actual LEGO colors? except that I need to fit a certain number of bricks of a certain colour. For example, I have 20 white, 28 ...
The LEGO Group released a few "mosaic" sets a while back, which came with clear baseplates and a bunch of 1x1 bricks. I have been wondering recently if it is possible to use an image as a reference ...