Am i able to post an image to my activity feed from outside xbox ?

Unfortunatly that wont be possible.

No, screens and videos need to be captured via Xbox or the Xbox Game Bar on PC, otherwise the Xbox Live feed would be overloaded with memes and GIFs.

Hello!

The best idea I would have is if you're able to log into a website that shows that you won, you could do this from your Xbox edge browser. Then take a screenshot of it and share it directly from your Xbox.

Actually, with the Xbox App on a PC you can download or UPLOAD captures to your feed.

I am having this issue too. I am in the preview programme. My issue was from 26 days ago. This is what is my issue in a bit if detail.

1. Cannot make a Post in the Activity Feed, but i CAN reply to other friends posts..

2. Cannot share a video to the Activity feed, but i Am able to on twitter fine.

3. The 'last 30 days' achievement leaderboard activity thread has me as 0, even though i have earned 350 or so achiev' points this week alone.

4. Achievements earned not sharing to the activity feed.

5. All of the above through the SmartGlass App..

Pleaee note that i have tried EVERYTHING from the powere re-set, to removing/reinstalling my profile from my XB1. I have tried my daughters profile on my XB1, and the activity feed works fine. So, this seems to be an issue with the 'SHARE' feature to my
Gamertag/profile, and is an Xbox live problem as i can share to twitter..

After trying to get help via Xbox support on twitter, they pointed me here.

Please help.