Retrieving a FB Fan Page Access-Token

I have a situation where I have to post a photo to a fan page via FB Canvas Application. My problem is that I only managed to post successfully being a page administrator. Is there some way any other normal user can retrieve the fan-page access_token and post successfully?

Url I am calling to retrieve FanPage access_tokens:

https://graph.facebook.com/me/开发者_StackOverflow中文版accounts?access_token=[user-access_token]

I am setting the following permissions :

email,read_stream,publish_stream,user_photos,photo_upload,manage_pages,offline_access

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What you want to achieve should work with an offline access token for your page administrator.