Providing this for anyone who might like it. I'm not a fan of the round artist posters, so I dug through the CSS to find how to change it. Along the way I found a couple other things.
The first rule restores the square artist posters, with a very slight rounding of the corners.
/* RESTORE SQUARE ARTIST IMAGES */
.cardContent-round {
border-radius: .3em;
}
This rule stops the posters from being distorted to fit a square (or round) aspect.
/* DON'T DISTORT ARTIST IMAGES */
.cov