Hello @WillieD64 ,
If it's an image you've uploaded to your Constant Contact library, then you'd need to copy its URL and link your button to that:
If the image is hosted in a different cloud drive, then you'd need to grab its share URL from that drive, and setup the button link with that.
See also:
Preparing images for library upload
Uploading images to the library
Linking buttons
... View more