I was about to "Save as..." when suddenly it struck me that this would be an incredible bait to spread a virus.
I think certain browsers have security limits on the file-extensions you download, which may include when image->"save as" is used.
Combine that with something like Safari's insistence at automatically exploding zipfiles on download, and you got yourself a party.
[0] https://docs.microsoft.com/en-us/security-updates/SecurityBu...
I remember being like you, believing no virus could come from an image or other data. I have been proven wrong enough times since then. We keep assuming things as programmers and sometimes we get it wrong and then there is a new wulnerability.