How can one remove an image from a screenshare recording?
One way to do it is to overlay the relevant part of the presentation with another image (could be a blank image). This is called picture in picture, which is often used to overlay another video across part of a background video, but of course the same principle works for still images too.
You need a video editor that offers such a feature, any professional editor can do it and probably many free editors too.
Basically, you have the presentation video as one track and add the replacement image as a second track above it with the duration limited to the time segment where the problematic image is shown. This overlay track will hide the underlying image. You can resize the overlay image, so only the relevant portion of the presentation is covered.
The exact steps depend on the video editor you want to use. If you don't have a video editor yet, you could try the free version of DaVinci Resolve and check out YouTube tutorials on the picture in picture topic to see how it's done with this editor.