Adding Picture to Locked Spreadsheet

[The Merg]

I am using Excel 2003 to create a spreadsheet that has locked and unlocked
cells in it. My goal is to lock the worksheet and allow entry only in fields
that are unlocked. I would like to be able to allow someone to click on a
field and then insert a picture. The problem I have though is that when a
worksheet is protected, you cannot add pictures. Does anyone know of any
workaround or macro that will allow this? I once found something that does
the trick for protected Word documents, but haven't for Excel spreadsheets
yet.

Thanks,
Merg