Problem Definition

At the moment, it is not possible to set a repository's avatar via API, this is only possible via the UI.

Customers managing their repositories as code also want to manage the avatars as code.

Suggested Solution

Allow users to set an avatar when creating or updating a repo via API ( https://api.bitbucket.org/2.0/repositories/workspace/repo_slug ) using the following property

"links": {
    "avatar": {
        "href": "data:image/gif;base64,R0lGODlhEAAQAMQAAORHHOVSKudfOulrSOp3WOyDZu6QdvCchPGolfO0o/..."
       }
 }

This is possible at the moment with project avatars https://developer.atlassian.com/cloud/bitbucket/rest/api-group-projects/#api-workspaces-workspace-projects-post

Workaround

Currently, it is only possible to set a repository's avatar from the website, there is no workaround to achieve this via API.