How to add logo to Contributions - Receipt (on-line)
This issue has been resolved.  I am almost too embarrassed to tell you what the problem was. 

All this time, I was working on the Contributions Receipts, but doing my tests on a Membership page.  As soon as I noticed there was also a Membership receipt it all came clear. So, if anyone else ever runs into this issue, remember if it's a contribution but not a membership, it uses the Contribution Receipt.  If it's a membership it uses the membership receipt.  

Thank you everyone for trying to help me figure this one out.  You did open my eyes to a lot of possibilities.