Feature: Simple merging of two images together

[adelin-b]

Hello, in the example shown on the website there is a lot of filters etc but I didnt found basic operation on images like merging two images together, which is an usecase that happen a lot in my current company and I wanted to find ways to optimize this.

For example i have a blue square and a red one, and i want to merge the image together to produce a new one:

And same for erasing :

Would become

[ben-black-tec]

I was looking for the same use-case, and I think I can get this to work with watermark function https://docs.rs/photon-rs/latest/photon_rs/multiple/fn.watermark.html But its not super fast.