That should work! If you want to remove filters, remove_query_arg() can be used to strip off undesired filter parameters.
Also, jetpack_photon_url() can be used independently of wp_get_attachment_image_src() if you have an image URL from somewhere, as jetpack_photon_url() has no dependency on WordPress’ image functions. As per the Terms of Service, you still need to connect Jetpack to WordPress.com if you were to do so.
Also worth noting is that in this case, you'd likely want a if( function_exists() ) wrapped around your calls, so that wp_get_attachment_image_src() would degrade gracefully without Jetpack.