How do you tell a classical guitar from a folk guitar in terms of appearance? Preferably with pictures please.

Theoretically:

The strings on a folk guitar are all steel, all 6 of them;

The strings on a classical guitar are nylon on the 1/2/3 strings, and steel on the 4/5/6 strings;

The head of a folk guitar is a wooden board, whereas the head of a classical guitar has two hollow grooves in the wooden board;

The one on the left is a classical guitar, and the one on the right is a folk guitar