Sometimes avatars are not displayed in notification emails that contain events with or from external accounts, such as Friendica.
Avatars of Diaspora users are displayed correctly.
A non-functioning (wrong?) link to the image is given in the source code of the mail.
However, the (Friendica) avatar is displayed correctly on the Diaspora website.
The email notifications use a smaller version of the profile picture. However, diaspora* does not resize the thumbnails itself, the URLs fixed within the user’s profile data, and this data is generated and sent by the originating node.
So this is either a setup-issue on sekretaerbaer.de, or a bug in Friendica.
works, and a = is used in the quoted-printable email format to signify a soft line-break. So maybe your email client has a bug - because that character probably shouldn’t be part of the URL (but that’s hard to say without looking at the raw source of the email)