Looking for a unity compatible 3-part image library

I'm trying to read image files(jpg,png,bmp) and do some processing a background thread. Texture2D loadImage doesn't work because it must run in main thread or coroutine. For the sake of cross platform, the image classes provided by .net framework in System.drawing don't work too. I have tried ImageSharp and ImageTools but they seems not unity compatible.

My basic requirement is to read the pixels from the image file.

Any help would be appreciated!