Hey RTYTHRFG
The icons are the size they are (20x20) as Agatio has patched it that way.
If you feel your icon has lost some quality, you can edit it and re-send to Agatio for upload if you would like.
To see it as it use to be in game (16x16) Agatio is willing to revert them if most people don't like the change.
To do it yourself would require manually editing within your personal files - which is something I cannot help with.
Plus you would be the only one to see it :/