Whenever I paste a picture, it multiplies that picture x2.

Whenever I paste another picture into the same post, it multiplies the first picture by 2.

Whenever I paste a third picture, it multiples the first picture again by 2, the second by 1.

Whenever I paste a forth picture, it multiplies the first picture by 3, the second by 2 and the third by 2.

Can someone like fix this?