...just found out this is one of the background choices for Mail themes in Yahoo Mail’s web client! The picture is apparently and appropriately called ‘Road Trip’ :P
Source: I have a Yahoo Mail account I’ve had since like...1998 when I was in Jr. High. I literally NEVER use it (my primary accounts are one Hotmail account and 3 Gmail accounts...don’t ask), but for some reason I do still sign into it once and awhile to keep it active...