Today I found a lora (a thin green snake) eating a large tree frog . I climbed to the top of the tree to get a closer look and realised how (as you can see in the photo) the snakeskin stretched and the scales spread out when the frog was in it's mouth. The snake may not look green and I would have agreed with you if I had not seen the real thing.
I expect you will want to know how the lora catches its prey. After seeing this one, it is not at all hard to write. The lora curles up and makes sure that the prey can't escape. It then lunges for the head. The surprised animal struggles and secretes poison but the snake is immune to the frog's defences.
Gradually, the snake unhinges it's jaws and works the finally dead frog down its throat, the animal staying there as a lump. We do not know how long it stays there. The lump eventually goes away, leaving the snake to do as it wishes.