Since 1.2 is primarily CSS cards for the responsive - you should be able to edit the colors in the ACP -> Style Properties to play with one that looks good.
You can also use some of @Shelley's examples for Notifications to put images in the corners, etc.
You could in theory always use a background-image on non-responsive and then when responsive kicks in set it up so it uses the background-color so it contracts/expands in responsive. That would allow for an easy fixed image on desktop layouts.
If that is css3 gradient you could add a box-shadow. If it's an image you'll have to add the shadow (outer-shadow) via a graphics editor. Judging by the screenshot you have a box-shadow already.