Use the Responsive code feature when you want to share the code for responsive serving with your web developer. You copy the responsive (RESS) code to the clipboard so you can share it with the web developer.
This feature makes sense to use if your website is on a third-party WCM. However, if your website is on AEM instead, an offsite image server renders the image and supplies it to the web page.
The selected asset and the selected image preset or viewer preset must be published to make the URL or RESS buttons available.
(Note that Dynamic Media - Hybrid mode requires you to publish image presets; Dynamic Media - Scene7 mode automatically publishes image presets.
HTTP/2 is the new, updated web protocol that improves the way browsers and servers communicate. It provides faster transfer of information and reduces the amount of processing power that is needed. Delivery of Dynamic Media assets is supported using HTTP/2 which provides better response and load times.
See HTTP2 Delivery of Content for complete details on getting started using HTTP/2 with your Dynamic Media account.