CJW’s save plugin is enabled on all games, the checkbox on the Game Details page is for use of CJW’s save menu extension, which requires the *sm_init code be present at the start of the game or there will be an error.
Which save system are you using?
Also yes, the width is 360 pixels and the height is 195 pixels for the game card picture. I adjusted your picture to fit the specs, hope you don’t mind.