Send file width/height in custom POST parameters

I notice we can send custom POST parameters but the custom parameters are set in the
render component setup.

Is there a way to access the image width/height to send alongside in the custom parameters?

No file, test, or entry point is named in the issue. Start by tracing how custom POST parameters are configured in the render component and how the uploaded image dimensions become available. Done means width and height can be included with the custom parameters, with behavior verified by the relevant upload tests if available.

Written by the indexing model from the issue text.