I'd be interested if anyone has tried it in real life, but I did an experiment this morning...
So, I took the big picture from the miniart website, and resized it to 'actual size' (it's about 350mm x 240mm). I then printed it out on a piece of paper and stood a model on it (no picture yet, I might try that later after work).
Each individual cobblestone is 5mm x 9mm. This, for me, is too big for 28mm models, and therefore probably too big for 1/48. It's down to personal taste - you may have to try it yourself.
Hope that's helpful :-)