Default Avatar icons missing from Discussions Option Page

The Default Avatar icons are missing from the Discussions submenu under the settings tab on my Wordpress multisite install - you can upload and see personal avatars just fine - and the default icons show up for people if they don't install a custom avatar - but the icons for choosing those default avatars are missing - this is a cosmetic issue, as I don't want my users to see broken images when they set their default avatars. Can someone help?

Here's a screenshot of the missing icons on the Discussion menu -

Here's the link URL the images are coming from

- there is no folder there (I deleted the Avatar plugin and then reinstalled the updated version which calls for the avatar folder to be in mu-plugins but it's trying to find the avatars in the wrong place - how can I fix that?

Thanks in advance! :slight_smile: