Really confused about the rss feed icon that used to be set on the index next to each node? I tried editing the little rss feed icon that used to be next to all the subforums... Reuploaded a new image which was the exact same size and file type... and now nothing is showing up.
Did you place the custom rss feed icon back onto the xenforo-ui-sprite.png ? exactly where the old rss icon was? if not you will need to do this otherwise placing it elsewhere will result in incorrect coordinates being used and you'll have to apply new coordinates i think in the style properties.
If you've used a custom individual image then you'll need to apply that to SP or extra.css with the new path to the image.