This is hard, because tbh, they are all great quality so being very nitpicky here (and I would vote myself out if I could, I hate my icon!).
2 least quality icons: 3 - The icon looks quite pixelated and blurry at the same time. The colouring is nice but some additional lighting could have helped make the icon pop a bit more.
4 - I like the painted colours! But the background is very wish-washy, and the cut of the subject(s) isn't very clean. Angel's body is so dark in comparision to everything else. Maybe using levels or a gradient map to make the blacks more neutral would have helped.
no subject
2 least quality icons:
3 - The icon looks quite pixelated and blurry at the same time. The colouring is nice but some additional lighting could have helped make the icon pop a bit more.
4 - I like the painted colours! But the background is very wish-washy, and the cut of the subject(s) isn't very clean. Angel's body is so dark in comparision to everything else. Maybe using levels or a gradient map to make the blacks more neutral would have helped.
1 best quality icon
1 - Amazing lighting.