Onion for metrics.torproject.org makes clearnet XMLHttpRequests
A query such as http://rougmnvswfsmd4dq.onion/rs.html#toprelays will send an XHR through onionoo.torproject.org rather than through tgel7v4rpcllsrk2.onion
For a hidden service, it seems preferred not to have any third-party clearnet requests.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information