binascii.Error if media file not present

Using pytest-html 3.1.1 and xdist 2.5.0

When passing a non existing file as media, pytest-html will raise an error during report generation.
To reproduce: Add extra.append(extras.image("doesnotexist")) in a report.

Actually I am looking for two things here

1. binascii.Error should not happen. What encoding should the passed 'content' string have?
2. How to reference local media, which does not yet exist as a file?

More details:

We are using 'extra.addImage()' in combination with pytest xdist.
When generating the html report, the media files from the different testing engines are not yet rsynced, so pytest-html will not see most of the files during report generation.

Because of this, the check (plugin.py 406ff, version 3.1.1)
is_uri_or_path = content.startswith(("file", "http")) or isfile(content)
is False.

Subsequently, the 'content' is treated as an external link, and decoded with this:

content = b64decode(content.encode("utf-8"))

This causes an binascii.Error, and no html report is generated.

The error can be triggered easily by adding an invalid media,like
extra.append(extras.image("doesnotexist"))
to a report.

The quickfix for us was to always set is_uri_or_path True.
Media files are referenced locally, so prefixing the uri with "http" or "file" is a bit difficult.

Reproduce the failure with extra.append(extras.image("doesnotexist")) and inspect the media handling around plugin.py 406ff. Trace the is_uri_or_path check and subsequent base64 decoding, then review the report-generation path used with pytest-xdist. Done means a missing local media reference no longer prevents HTML report generation and its handling is covered by tests.