How to process and generate thumbnails in Go language

package main
import (
    "fmt"
    "os"
    "image"
    "image/color"
    "image/draw"
    "image/jpeg"
)
func main() {
    f1, err := ("")
    if err != nil {
        panic(err)
    }
    defer ()
    f2, err := ("")
    if err != nil {
        panic(err)
    }
    defer ()
    f3, err := ("")
    if err != nil {
        panic(err)
    }
    defer ()
  
    m1, err := (f1)
    if err != nil {
        panic(err)
    }
    bounds := ()
    m2, err := (f2)
    if err != nil {
        panic(err)
    }
    m := (bounds)
    white := {255, 255, 255, 255}
    (m, bounds, &{white}, , )
    (m, bounds, m1, , )
    (m, (100, 200, 300, 600), m2, (250, 60), )
    err = (f3, m, &{90})
    if err != nil {
        panic(err)
    }
    ("ok\n")
}