Yes, put it back the way it was as default because this code is universal and will effect avatars site-wide...
And if you insist then apply as follows:
div.ow_avatar a img {
height: inherit !important;
width: 70px !important}
You
will see site-wide, per example Photo, Video and etc - comments that the
avatars don't fit proper, so like a domino effect avatars site-wide are
effected, so here you will find yourself having to apply separate codes
to fix theme all, a real pain in the keister if you ask me, I will
give/Supply here the fix for Photo comment avatars.
div.ow_comments_item_picture div.ow_avatar a img {
height: inherit !important;
width: 40px !important}