speedup by making image thumbnail before analyzing

making image a thumbnail before analyzing makes the analysis part of the code run in constant time since all images are now 200x200 instead of 1400x2000 or 3600x4800 or whatever

on the small test images, 10x speedup, on larger 1000x1000 images, 30x+ speedup

using thumbnail smaller than ~200x200 starts affecting results (not passing some tests etc)