Every time I try to upload a YouTube custom thumbnail, I keep getting a "try again" message. I've tried resetting Firefox back to default, uninstalled/re-installed the web browser, I've made sure my thumbnails are the correct size and file type(which they all are). I'm not sure what else to do. Every time I want to upload a custom thumbnail, I have to use Google Chrome. I'm trying to avoid using Chrome more than I have to. If anyone could help find the solution, that would be great. Thanks! P.S. I added a picture to show the error I keep getting.