These domains are supported for hosting image files which you can use when creating listing:
1. Please check your uploaded images from time-to-time as some domains may have expiry on the hosted files.
2. The URL submitted must be directed to the image file itself and not the the image hosting page. You can retrieve the image file URL by opening the image in a new tab or copying the image address, as illustrated below.
For Dropbox users, you may Copy Link of your file, and change the URL from dl=0 to raw=1