Here are some technical info.
Q. I'm not Instagram user. Can I use InstaWallpaper?
Even if you don't have Instagram ID, you can set InstaWallpaper to your Twitter account by using everyone's photos in Instagram.
Q. I got an error (or blank image) when I clicked "Preview" button.
Please set privacy to "OFF." Enter your InstagramID with halfwidth alphabet or digit character. Otherwise, there are possibilies that Instagram API is not respoinding for your ID. Please try again in a couple of hours' time.
Q. How can I set created wallpaper to my PC/Mobile/Tablet?
It really depends on your device type and model...