That’s a bad idea! You should never use something off the internet if you don’t know where it came from and who to credit, because it’s theft and you can get in major trouble.
Anyways, to the poster of the thread, you should check out: Blanket Overlays For Every Episode Bed
And in regards to making one, hmm, I’m not sure but you can always request for one in art resources, check out Pixabay or try an app like PicsArt. Hopefully someone will come along with a much cooler answer 