proxy_ignore_client_abort will continue to fetch from upstream even if a client aborts the connection. This is highly recommended when cache is being used. If a client leaves/refreshes the page while a user's avatar or some other media is halfway loaded, the cached copy might in some cases be broken. Leaving future requests to the same URL broken until cache expires.
The built-in nginx default does not allow users to upload images
larger than 1 MB. This increases the maximum request size to match
the default Pleroma config upload_limit parameter. Some helpful
comments were also added.