Pixlr hijacked my ability to open attachments within FF(Mac)

[mjrs]

On my Mac, whenever I try to open a photo or document attachment in Gmail or a document on any web page in FF, it pops another tab, but then, instead of using Preview like the FF Preferences are set, the tab blackens and presents a dialog saying,"Whoops! There was a problem displaying this image." It suggests third-party apps like Pixlr Editor, Pixlr Express or PicMonkey, or Download, or shows a rectangular button with the upper half of a Google logo and saying, "Connect more apps..." and that takes me to a multi-page listing of third-party apps. I don't have any Pixlr add-ons or extensions. Nevertheless, is some malware causing this? How do I get back to getting FF to open .PDFs and .jpg and.jpeg, etc. in that tab or in Preview, instead of this goofy dialog?

[therube]

Any change if you restart in Safe Mode?