The problem is: it still takes a lot of processing time using System Graphics.
Yes because thats windows gdi its slooowww.
What I'm trying to do is to read an images from a file and slowly zoom into them at 25 fps. The problem with system drawing is that I need to crop and resize images,
What you would want to do in monogame is learn how to use a rendertarget create a camera and or learn how to use a pixel shader..
What I'm trying to do is to read an images from a file
(FILE IO) is the slowest texture operation no matter what you use.
Typically you load in as much as possible at the start from file you just load it from file to the videocard, and if need be as you go. Is this a image editing app your making ?
I can set a windows form's parent to the HWND and I can set the windows form's background to the image I want.
If your trying to get monogame into winforms ?
Im pretty sure its been done before, maybe someone who has done it can post a link to a tutorial for it.
There are however ui's for monogame if you just wanted buttons and stuff inside a monogame window. Thus keeping your app far more cross-platfom that way.
As jjag said it might be easier to use sharp dx directly.