Welcome to the forum!

When you overlay, I guess you want the inserted picture to be the same size? As such, both pictures would be there but the overly would be the only one directly visible.

When inserting the picture, would you want it linked or embedded?

A short example file might be nice to work with to help you best. Maybe just 3 image files and an example XLSM with 3 rows of images. Click the Go Advanced button in lower right of a reply. Then the paperclip icon or click the Manage Attachments hyperlink below the reply block to attach the zip file.