enlarge square image with a round blurred frame

[moul]

the new UX #73 will use round track images on top of vinyl discs, but we always have squared thumbnails by default

I started playing with full CSS here -> https://codepen.io/moul/pen/bGeOXMo

I think that something cool would be to keep the square image clear and unmodified, but add a blured round border that matches the border color of the original image

Keep in mind that we can generate an image from server side