Gray line around image placed in Illustrator 2020

Please see attached screenshot, which I hope will explain things. I rarely work with photo images in Illustrator, but the vendor requires final art be in .ai. BTW, this is for a trade show booth around 6ft X 4ft, and the art has to be 100% of full size. I'm working with transparent TIFFs.

Is the thin gray line appearing around the image just an Illustrator thing and won't print? It goes away on Overprint Preview, but not if they're embedded. They don't appear in the PSD file I've saved them from. 

I'm sure there's a simple answer. Thanks in advance for any help!