Update SendBird User Profile

Question

I want to update user profile of SendBird, for that i am calling

PUT https://{region_identifier}.sendbird.com/v3/users/{user_id} url

and passing request Body as

{
  "nickname": "Johnster",
  "profile_url":"https://sendbird.com/main/img/profiles/profile_02_512px.png",
  "issue_access_token": true             
}

Here profile_url is of string type, But if anyone choose image from gallery or capture by camera in that case we get bitmap data, i am converting bitmap into Base64String but is not accepted by api.

How i can pass image taken by camera or gallery as string type?