Problem with fetching photos of private O365 groups

As you probably know in O365 we may create groups which has one of the following visibilities:

• Public
• Private

Everybody in your organization may join/leave public groups while for private groups only owners of this group may add you to the group. In this article I will describe one problem related with fetching private group photos via Graph (see also my previous article where I mentioned another problem related with groups images: Why you should be careful with /groups/{id}/photo and /users/{id}/photo endpoints in MS Graph or unintentional getting photos of big sizes in Graph).

In order to fetch group photo the following Graph endpoint should be used:

https://graph.microsoft.com/v1.0/groups/{id}/photo

First of all we need to mention that this endpoint is available only via user delegated permissions (it doesn’t work with app-only permissions). If we will try to fetch photo of some group in Graph explorer using service account which is not member of this group we will get 404 Not found error:

After we will add the same service account to members of the same group image will be retrieved successfully:

Even if we will try to fetch photos of private group under global admin account which is not member of this group – we will still get 404 Not found. So the only way to fetch photo of the private group is to add user account to members or owners of this group. Be aware of this problem when will plan groups images fetching functionality.