I understand that according to the current documentation, images must be uploaded from a public URL when using the Messaging API. Could you please confirm if this is still the case? If so, could you please provide the reasoning behind this requirement

I'm interested to know if there are any future plans to enable direct attachment uploads for images, similar to the capability provided for videos and audio files in multi-form data format

Your clarification on these matters would greatly assist me in planning and developing my application.