Why are pictures grainy, Photos are usually very crisp. This time every one was grainy like low res when I have it set on High. The camera is a Canon PowerShot S3 IS

You may have the ISO setting too high.
Try ISO 200

Graininess can be caused by a high ISO setting while taking pictures in low light situations. You could also have the picture quality set to a low megapixel setting.

Hi Usually outdoor picture are good within small compact camera. They designed like that. But now your unit just have flash pcb defective. When flash function work, your picture will be good indoor. Regarding your flash unit would be brown fuse or replacement of flash unit. It is 50 and 50 chance. Your local repair shop would charge around $35 to 95 depend on what they really want to charge. Thanks and best regard!

Unfortunately with higher mpxs sometimes you pay for it with higher noise levels. The smaller pixels are more sensitive and can cause noise. A couple of things you can do to help control the noise is make sure your pictures not underexposed, you may need to bump up you exposure compensation a little as long as you don't end up too bright.
You can also try to shoot with the lowest ISO setting your camera has. High ISO = NOISE!
Last you can run your photos through a noise reducing program such as"Noisware" their community edition is free. http://www.noiseware.com/download_nwsa.aspx
PS Contrast settings will do nothing for noise.

If you are taking pictures in low-lighting conditions without flash, then the pictures will appear grainy. Set the ISO to a lower number (try ISO-100 to start with) and use the flash to compensate for low-light conditions.
This should improve the grainy appearance of your photos.

In low light, when taking photos on 'automatic', the camera may set the ISO to high sensitivity which can give a grainy image. In the menus you could try switching ISO out of automatic and set it to 100 at most.

You need to set the ISO to a high number. Too high and the pictures will be grainy...you'll need to experiment.

check to see if your image stabilization is on (shaky hand). turn this feature off. also check the properties of your image to see if the iso is set to automatic. high iso, such as 800, will cause this in cameras

just switch to regular mode but the pictures already taken will unfortunately be like this sorry

You should take your camera to service.

Normal cameras are meant to work above 0 deg C (32 deg F), but usually they work even at -15 C (5 F). When you work below the freeze point there may some anomalies, usually LCD turns blue or purple but photos look OK on a computer. Sometimes the camera refuses to take photos or shows bad focus, lens zoom mechanics get stuck etc. And you always experience significantly shorter battery life when in the cold.

It's a good idea to keep the camera in a warm bag and take it out before shooting. You can also keep it under your coat if you're not practicing a sport like skiing (because of body moisture).