virtual background serves as static picture?

Yes, you can use a static image as a virtual background. However, a virtual background only works when your camera is turned on it cannot replace your video if your camera is disabled. 

If your goal is to display a static image instead of live video, Zoom doesn't currently support using a virtual background with video turned off. Other participants will see your profile picture (if you've set one) when your camera is off, rather than a custom static image.