Your pics are fine, and so is your camera. You have an option called "Overlay Bright/Dark Area" turned on, which shows you parts of the pic that are over or under exposed. You can turn it off in the menu, or you can use it to advantage, to see at a glance when a shot isn't optimally exposed.
It's common for small bits, say highlights off chrome trim on a car, to be flashing, but if large portions of the shot are flashing, you might want to change the exposure and try again.
Oh, and welcome to the forum!