For a relaxed but not baggy feel, the small size is a solid choice.
Banksy-Inspired Comic Fire Starter Street Art T-shirt
A nice touch is that the small size has a tighter knit around the edges.
Banksy Butterfly Girl Street Art T-shirt
What stands out about the small is its precise cut around the armholes.
American Beauty Album Cover Art T-shirt
You will notice the small size keeps the shirt from looking oversized.
Album Cover Art for Fly By Night T-shirt
You will notice the small size has a narrower chest panel for a snug feel.