menperluas talks about the volume as in
memperluas ruangan = expanding the room
While if its a picture (gambar) were talking about, the image is stretched to make it bigger as in enlargening it.
So the correct answer is memperbesar
Correct me if im wrong
...i agree - memperluas is about space or volume (3D), while memperbesar is usually used for 2D things (like pictures or sheets of paper)
...membesar/membesarkan however has the general nuance of to grow/rear (a child, pet, plants, etc)