You can use Photoshop to extract quality still images from videos. Most video cameras nowadays (including smartphones) shoot 1080 HD video, which yields a single frame of 1920 x 1080 – or about 2MP.
There are a number of ways to pull still images from video clips and even ways to increase the resolution when you combine frames. Photoshop Principal Product Manager Bryan O’Neil Hughes explains how to do so in the above video.