If you have no profile picture because you deleted yours, Zoom will attempt to find one when it next syncs with MIT. Your MIT ID picture will then return as your profile picture. If you do not want to use that image as your profile picture, replace the default image with your own customized profile picture. It doesn't have to be a picture of you. You can use an image of your pets, favorite coffee mug or a generic image like one of these:
Click on the image to save it, then upload it to your Zoom profile.