With Steam now letting you use custom art for game covers, i was approached for a commission to re-do an entire Steam library using screenshots i've taken over the years, which i thought would be fun experience (with the added bonus that i could use them for myself as well!). When you use the right size and dimensions for the images (and find decent quality logos), it can look pretty good, especially if Steam was just using some low quality placeholder pictures to begin with. You can even add custom banners/recently played headers.