title: Blend pixels on .net core
body: <p>I am trying to overlay a part of one image on top of another image on .net core (code needs to be cross platform).</p>
  
  <p>I considered using ImageSharp since it supports win,mac and linux.
  But i couldn't find pixel blending on their features list, although i saw that you can access an individual pixel.</p>
  
  <p>So the use case would be, i have two 4k Png images and i want a small part of the first image (roughly 10% square of the overall image) to be overlayed on top of the second image (but not the whole image just the same 10% space) and get the area where the merging happened as a new Jpeg image.
  (the source PNGs have some degree of transparancy).</p>
  
  <p>I considered cropping out the two parts i want to merge from the two 4k images and then blending them to get the final image, but that is slow for the needs of the project I'm working on.</p>