Seperate image file vs Sprite sheet

Game Mechanics
#1

I’m about to add some images to my game and i was just wondering if having separate image files was faster than having a sprite sheet. I know the obvious reason for having a sprite sheet would be less memory but for right now, my game isn’t really memory heavy and the sprites I’m going to use aren’t very heavy either. I know that mincraft just recently changed to all separate images for it’s sprites and I didn’t see any significant difference in performance after it happened.
Thanks in advance.

btw: I’m using Java2D

#2

Sprite sheets are more efficient because you only have to load them once. Then, you can just cut them up. Individual images have to be loaded individually, obviously. More here: http://gamedev.stackexchange.com/questions/7069/2d-graphics-why-use-spritesheets