Hi,
My apologies for the inconvenience.
This issue was fixed in beta. If you are facing it there are two possible reasons:-
1. You had older version of MediaPress installed on this site at least once(beta version)
2. Or you are on multisite and you have activated this plugin network wide.
In the first case, we need to update the settings.
Please visit Dashboard->MediaPress->Settings->General tab make sure that you have the extensions specified there. Please see this guide to specify the extension
https://buddydev.com/mediapress/topics/getting-started/settings-options/general-settings/
If it is the second case, Please network deactivate it and only activate it on the Main site(where your BuddyPress social network is located).
Please let me know if that helps or not?
Thank you
Brajesh