best approach android to rest-api

I am working with a REST-API to receive a picture from android gallery.

I read some articles that converting having android to convert image to BASE64 and sending it to rest-API is not a good approach.

Anybody has thought for this?

The problem with base64 is that it adds 33% overhead to the initial size of data.
Pictures are usually in the KB to MB size range which can be a real performance issue on bad network connectivity.

so whats your approach on this?