How Can I Overlay and Manipulate Images with Specific Positions, Rotations, and Z-Indexing in Golang?

package main

import (
    "fmt"
    "os"
    "image/draw"
    "image"
    "code.google.com/p/graphics-go/graphics"
)

func main() {
    // Load background image
    bgImg, err := os.Open("bg.jpg")
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }

    // Load and prepare image 1
    img1, _, err := image.Decode(bgImg)
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
    bgImg.Close()

    // Load and prepare image 2
    img2, _, err := image.Decode(os.Open("img2.jpg"))
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }

    // Create a new canvas for compositing
    finalImg := image.NewRGBA(image.Rect(0, 0, 800, 600))

    // Draw the background image onto the canvas
    draw.Draw(finalImg, finalImg.Bounds(), img1, image.Point{0, 0}, draw.Src)

    // Rotate and draw image 2 onto the canvas
    rotOptions := &graphics.RotateOptions{Angle: 3.5}
    graphics.Rotate(finalImg, img2, rotOptions)

    // Save the final image to a file
    output, err := os.Create("output.jpg")
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
    err = jpeg.Encode(output, finalImg, &jpeg.Options{jpeg.DefaultQuality})
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
    output.Close()
}