Added a simple free plugin to set the default featured image here if none is selected, this is why you will see the same image on many of my posts here. I have not been creating any WordPress code lately but I have an idea for a featured image to be set if none is selected but this would create a image of your desired proportions with the post title. This would be very bland and boring so color background, text font-color, and text coordinates would have options and possibly more would be added to style them.
Most likely some preset and/or randomized feature in the creation process. Anyway just an idea that I have wanted for awhile instead of using a premade image or default. With this your site would have better design flow and all featured images would be different.