A lot of size comparisons and art work get the size of quadrupedal Pokemon wrong because they measure from the top of the head. This is incorrect as you're supposed to measure from the highest point on the back, usually the shoulder. For reference, each square is a foot and the human is about my height at around 5'9ish. Eevee is 1'0, Umbreon 3'3, Jolteon 2'7, Ninetales 3'7, Arcanine 6'3, and Shaymin-Land 0'8 (and appears really tiny because its back is higher than its head). It's not perfectly accurate since I eyeballed the inches and I don't have perfect profile views of any of the Pokemon in question (Ninetales especially since I had to use a sprite). But, it should give you a general idea of their correct heights at least!