Post a photo from a message to a VK group?

Question

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Hello!
There is a task: a photo and a "code word" are sent to the group's messages, the bot recognizes the "code word" and creates a post in the group. Everything is done and almost works .. except for the photo. If you attach a photo from the user's already available in VK to the message, everything is fine. If you add (upload) a new photo, everything works, but does not attach a photo. At the same time, a report is created that everything has been worked out, gives out a photo ID of the photo111_222_333 (-code) format, gives a link in the format https:\/\/pp.userapi.com\/c111111\/v111111\/11111\/111111.jpg (all from callback api). A direct link (vk.com\photo...) does not allow opening this photo.
Can you tell me where the dog is buried?

Answer 1

If an object belonging to another user is attached, its access_key should be added to the attachment in the format __, For example:
video85635407_165186811_69dff3de4372ae9b6e

data access key access_key