Excel and Pictures

I would like to understand how Microsoft Excel handles pictures when it is
deleted.

I have come to realize that the pictures that are inserted into Microsoft
Excel and then deleted, are not really deleted but hidden between lines
between the rows.

I have tried the activesheet.shapes.selectall function to try remove it but
it still is not perfect.

I deal generally with a lot of pictures in Excel, and would really like to
understand how Excel handles pictures specifically.

Thank you for your time.

Ooi Kean Jin