Is there an app to overlay an image permanently on top of the entire screen?

[Android Central Question]

Suppose I have an image (say a jpeg or whatever format is nice) with exactly the same width and height (in terms of pixels) as the screen of my android phone (I have a Galaxy S7 edge running android 8.0.0). Is there an app that allows to permanently overlay this image (with prescribed opacity) on top of my phone's screen, ideally without requiring root access? If the opacity part is difficult, one could build it directly into the image using a format that supports transparency, like png.

If the answer to the question is negative, would it be easy to write such an app?

 

[ManiacJoe]

What you describe is an interesting solution.
What is the problem you are trying to solve?