Please contact directly with support to provide more information and they will assist you to resolve this matter.
Please contact support, so they can assist you on this: http://www.xtube.com/contact
Unfortunately this option is not available at the moment, thumbnails are automatically generated from each video, but thanks for sharing your suggestion with us, we will consider it for future use :)
Hello Raka! How does the URL block you from finding your favorite videos? If you favorite a video then it’s immediately added in your list:
We’d appreciate if you could share further details. Thank you