Why should the app save the images to some other location than in the gallery? As pichlo noted, I'm not going to invent the wheel again if some other app already provides means to for example delete the image.

What do you mean by "rendering of some common programming languages"?

And yes, taking an image of a screen is not going to work so well in most cases, the background is too hard for the preprocessing step unless there are clearly pure black/white regions.