Why do the pictures on my S7 look grainy?

[AC Question]

I took a lot of pictures inside yesterday with my S7 and none of them are any good because they look grainy. I have not changed any of the factory settings. Any suggestions?

 

[Rukbat]

Low light = grainy pictures. Or it could be a malfunctioning camera.

 

[oldmustangs]

Guessing low light since I was not able to use my flash. It does take good pictures outside. Thanks.