We unfortunately can’t do that because we automatically try to downsize images until they meet the size requirements or we spent too much time on the server trying to… Since there is no way to know the size of an image after downsizing before actually doing it, the client has to wait for the upload to finish and the server to spend time trying to downsize the image.
The only way we can fix that would be to do the downsizing operation on the mobile before uploading the image. This is on my list but near the bottom at the moment.