Image Urls appended and broken

I am experiencing the following problem, and looking for someone that can help. I have some image urls that come up appended. A string is added by some process at the end of the image url. So if the url was https://www.happyfamilyart.com/wp-content/uploads/2014/10/CherryBlossom34.jpg They are changed to something that looks like this: https://www.happyfamilyart.com/wp-content/uploads/2014/10/CherryBlossom34-e1433729049997.jpg After which, the media url is the appended one, and the image links to the original url but labels it as Custom Link. Occasionally the image links will come up broken, and then ‘purge varnish’ temporarily fixes them.
I have gone through FTP, and removed the appended image instances, only to have them reappear shortly thereafter.
I don’t use any cache plugins.
What could be causing them.