image_transport should always be used to subscribe to and publish images. It provides transparent support for transporting images in low-bandwidth compressed formats. Examples (provided by separate plugin packages) include JPEG/PNG compression and Theora streaming video.
https://anaconda.org/robostack-jazzy/ros-jazzy-image-transport/badges/version.svg
https://anaconda.org/robostack-jazzy/ros-jazzy-image-transport/badges/latest_release_date.svg
https://anaconda.org/robostack-jazzy/ros-jazzy-image-transport/badges/latest_release_relative_date.svg
https://anaconda.org/robostack-jazzy/ros-jazzy-image-transport/badges/platforms.svg
https://anaconda.org/robostack-jazzy/ros-jazzy-image-transport/badges/license.svg
https://anaconda.org/robostack-jazzy/ros-jazzy-image-transport/badges/downloads.svg