Hi Kostya,
Do you remember we discussed images from Gmail (sender) profile. (Sorry, I cannot find the thread where we discussed this question.) Here is a quick followup.
I just came across this option in Gmail settings: (under "General" tab,
My picture:
Select a picture that everyone will see when you email them.)
Here is the support page explaining that and the related options:
https://support.google.com/mail/answer/35529?hl=enUnder "Visibility" they write:
"Visible to everyone: Anyone who you email, or who emails you, can see your picture."I am not 100%, if "anyone" means "anyone who uses Gmail", or there is a link to that image accessible for complete "outsiders". IFF it is the former, - I am guessing, any mail client can utilize it.
It might (or might not) use the API that you'd referenced at that point.
I am not pushing for any action (I don't care for those images - this is more of an "academic" interest for me), just sharing the information. Please, forgive me if you've known about it.