resize-png.go

package main

import (
    "github.com/nfnt/resize"
    "image/png"
    "log"
    "os"
)

func main() {
    file, err := os.Open("image_1.png")
    if err != nil {
        log.Fatal(err)
    }

    // decode jpeg into image.Image
    img, err := png.Decode(file)
    if err != nil {
        log.Fatal(err)
    }
    file.Close()

    // resize to width 1000 using Lanczos resampling
    // and preserve aspect ratio
    m := resize.Resize(437, 315, img, resize.Lanczos3)

    out, err := os.Create("test_resized.png")
    if err != nil {
        log.Fatal(err)
    }
    defer out.Close()

    // write new image to file
    png.Encode(out, m)
}