Which version of InDesign and OS?
Check whether the image is on a master page or whether the layer has been locked.
ok, he's using Creative Cloud, the 220.127.116.11 x64 build running on Windows 10.
the image is not on a master page, and there's only one layer in the document and it's not locked.
The image itself could be unlocked. Locate it in the layers panel.
I think Bob meant the image itself might be locked (even if the layer it resides on is unlocked). Try Object > Unlock all on Spread.