Basically what Im trying to do is this
https://graph.microsoft.io/en-us/docs/api-reference/v1.0/api/profilephoto_update
I need to mass update all the profile photos
Ive already have the server endpoint application setup with correct permissions.
the problem is that i do not have the file itself but just base64 string value of the file.
is there a possible way to update the profile pictures with just the value?
As per the documentation you've already referenced (https://graph.microsoft.io/en-us/docs/api-reference/v1.0/api/profilephoto_update) the Microsoft Graph only accepts profile picture images as bytes.
You can easily convert your base64 string value to bytes using the following snippet.
byte[] bytes = Convert.FromBase64String("R0lGODlhAQABAIAAAAAAAAAAACH5BAAAAAAALAAAAAABAAEAAAICTAEAOw==");