Hello,
From your description, I am not so sure what you want to be done. Please confirm my understanding.
You want 3 spreadsheets top - center - bottom. In each spreadsheet, you want to put in it a background image.
top spreadsheet -> put top background image
center spreadsheet -> put center background image
bottom spreadsheet -> put bottom background image
When you open the spreadsheet, based on unique address in the cell, it should look for and insert the corresponding image (from an image resource - e.g. a folder) to the spreadsheet and adjust rows/columns to fit the image.
Could you please make clear your requirement in chat then I can make a demonstration and sent you?
Thank you