This question is sort of half code, half a legal question.
I'm researching what can/can't be done in terms of apps that make use of YouTube embeds as content such as:
Other answers on StackExchange suggest that it may not be advisable to use the thumbnail image generated by YouTube on another website:
However, I see that Popular50 and riv.yt link to the image generated by Youtube in their style-sheet rather than copying them to their site or loading them through an HTML image.
Popular50.com uses inline styles like this:
<div class="wrapper" style="background-image: url('https://i.ytimg.com/vi/4CbLXeGSDxg/hqdefault.jpg')">...</div>
Is this a legitimate way to do this? (From a legal perspective) The link in the css links directly to the original file on YouTube.
Thanks very much