Since the docs are a bit sparse, this is a very short post on how to draw a pixel:

use image::{ImageBuffer, Rgb};
fn main()
{
    let green = [0, 255, 0];
    let red = [255, 0, 0];

    let mut image = ImageBuffer::<Rgb<u8>, Vec<u8>>::new(200, 200);
    image.put_pixel(5,5, Rgb(green));
    image.save("output1.png");

    for i in 1..100 {
        image.put_pixel(i, 5, Rgb(red));
    }
    image.save("output2.png");

}