Completely white outdoor photos usually mean severe overexposure. Since it started after changing batteries, first check whether the camera reset its settings.

Try these steps:

• Set the camera back to Auto mode.
• Turn the flash off for daylight shots.
• Check exposure compensation and make sure it is set to 0.
• If ISO was reset, use Auto or a low ISO outdoors.
• Make sure no scene mode is selected that could force a slow shutter or bright exposure.
• Reset the camera to factory defaults in the menu, then test again.

If indoor shots are sometimes fine but bright outdoor scenes are always white even in Auto mode, the camera may have a mechanical fault such as a stuck shutter or aperture, which can cause too much light to hit the sensor. In that case, compare the live view and saved image, and if the problem persists after a reset, the camera likely needs repair or replacement.