A picture is a powerful tool to show you exactly what you want to be seen.
This picture shows one of my favorite models in the fitness industry: Lazar Angelov!
On the left, you see a huge arm, well defined while on the right, Lazar is very skinny as if they were two different guys.
Light, distance are as many parameters that you should take into consideration while doing a photograph shooting. In general, the light will help to show the shadows created by your muscles resulting in looking bigger.
Distance will also play a role in making your body look smaller or bigger.
Never forget that a photo rarely shows the reality 🙂 and you too, maybe you are more muscled than the photos seem to show!