HI aklwb,
Images in cells are 'format,' not 'data.'
To remove 'data' from a cell, you can click on the cell to select it, then press delete to delete it.
To remove 'format' from a cell, whether that 'format' is italic type, bold type, colour fill or image fill, generally requires a menu choice or some action in an Inspector.
This is a user to user community. Apple team leaders and development teams don't read these conversations or participate in them. Apple's monitoring of the conversations is minimal, and primarily concerned with adherence to the terms of use. The only direct Apple participation is by "Community Specialists," who do pick up questions that have not had a user response within about 24 hours of posting, and provide suggestions regarding knowledge base articles usually pertinent to the issue.
Revising the software is beyond the scope of these communities. To request that type of change, you should go to the Numbers menu, choose the second item, Provide Numbers Feedback, and send a Feature Enhancement request directly to Apple.
Regards,
Barry