I've been having issue for about a week now, that I can't post screenshots or any image into steam chat or into steam group chat.

Something we have extensively employed in our gaming sessions to mark points of interest or objective for teammates without having to stand by it and wait for everyone to arrive.

Sometimes it luckily slips through but for roughly a week now 99% of images fail to post with
"Failed to start upload: A server error occurred. (25)"

I'm Running the stable steam version but support told me to post this here.