I'm trying to add my logo to a sales receipt and invoice. I can select the logo, the system say processing but when I click Save nothing happens.

Hi there, 

Welcome to the Community. It's essential you're able to use the program without running into issues.  I'll be glad to steer you in the right direction with this. 

To get started, I'd like to start off by troubleshooting this issue to determine if it's a browser-related issue. Clearing cache and cookies is a great way to clean your browser allowing it to work more efficiently. Here's an article that shows you how to do that: How to clear cache and cookies. If this doesn't work, I suggest using a private/incognito window to see if that works instead. Try this out and let me know what happens.

I'll be one message away in case you need further assistance.