Vilz...to my knowledge, I have never downloaded a WindowBlind that actually applied the wallpaper with it. Like you said, you would have to look in the folder to find, However most do not come with a wall in the folder.

I suggest you try Suites. With the push of a button, you will get everything the Suite has to offer.(depending if you have the programs)(ex. If you do not have IconPackager, you will not receive the Icons in that suite) You will need this program in order to apply https://www.stardock.com/products/winstyles/ Very simple to use.

OR......just ask the authors where they got the wall for the screenshot in order to have it.

If the author has used a wallpaper that is not his/her own, they don't always include a link to it. sometimes you just have to hunt it down yourself, or if possible email the author and ask where they got the wall, they might have the link in their own bookmarks if it's offsite.

suites just gathers the skins for the various programs you are using currently and lets you know if there's a skin that matches in other programs you aren't using(in case you want to install those programs too.)
if you like a whole suite's design, the suites program will save you the time and trouble of hunting down all the elements of that whole.