However, Google in its infinite wisdom lists followers without images last in its follower lists. So when a no pic follower signs up to follow you, you will see your follower number has gone up but unless you click right through to the end of your list of followers you won't be able to see who it is.
If you are a "no pic" follower, I suggest that you do go into your Google profile and add an image. It doesn't have to be a photo of you. It can be anything. I have a water scene on my own one rather than a photo.
It is easy to change to being a Pic Follower. Just go to your profile - one easy way to do that is to go to a site you follow and sign in . Your icon will then come up and, if you click it, you will go to your profile - up the top right you will see "settings". Click on that and you will be able to edit your profile including putting in an image.
Just make sure you crop or resize your image so that it will be accepted. You can't use large image files for this. Good luck.