About a week ago, a new and strange image appeared on my start screen (see round image in uploaded file). It looks like a detail of a prickly pear. Wtf?? I have no image like this in my files, and I can't get rid of it. Right clicking does nothing. I'm concerned this is/points to malware on my system. Full scans with Norton, Bitdefender and Malwarebytes all come up clean.
Has anyone else encountered this? All thoughts welcome.