The picture on the left represents the reactants in the equation and the picture on the right represents the products. Does this reaction follow the law of conservation of matter?

According to Law of conservation of matter," matter can neither be created nor destroyed but is conserved and remains constant over time'.

In above picture let suppose the Blue balls represent N₂ molecule and White balls represent H₂ molecules.

So, left picture represent reactants,

2 N₂ + 6 H₂

And , right picture represent products,

4 NH₃

So, there are 4 N atoms and 12 Hydrogen atoms in reactants and 4 N atom and 12 Hydrogen atoms in products. Means the mass of elements is conserved. The overall reactions is as follow,

2 N₂ + 6 H₂ → 4 NH₃

Result:
Yes! This reaction follow Law of conservation of Matter.