A: If you are using a 3rd party ad server downstream from Addroid (i.e. Doubleclick Campaign Manager, AppNexus, etc), a static backup JPG will often be required by the ad server in order to setup creatives. When an Addroid tag serves, it performs a check for compatibility and connection speed, then serves video if supported. If video is not supported, then Addroid will serve the endframe in the creative as a backup.
Even though the 3rd party ad server requires a static backup, it will never be served when Addroid is used. Since most 3rd party ad servers have a hard file size limit (typically 40-70K), we recommend exporting JPG files below this limit even if the quality is poor since they will never be served.