Video Thumbnails look horrible! Is there any way to fix them?

Im using VIMEO to embed my videos. The thumbnails look great in VIMEO, but horrible on the SqSpace site!  Even if i replace the thumbnail with an image in Vimeo, they still come out horrible. Is there any way to fix this?  its enough to make me want to leave SqSpace for another host.

Have you tried adding a custom thumbnail within Squarespace?

Why didn't i see that!?!  Thank you!

Yes they do and I brought this to the attention to Squarespace months ago and they choose to not fix it. Why even have the option if its not working.