Go - 画像リサイズ

package main

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

func main() {
    f, err := os.Open("./data/hoge.jpg")
    chkErr(err)
    img, err := jpeg.Decode(f)
    chkErr(err)
    _ = f.Close()

    thumb := resize.Thumbnail(300, 300, img, resize.Lanczos3)

    out, err := os.Create("./data/thumb.jpg")
    chkErr(err)
    defer Close(out)
    err = jpeg.Encode(out, thumb, nil)
    chkErr(err)
}

func Close(c io.Closer) {
    _ = c.Close()
}

func chkErr(err error) {
    if err != nil {
        log.Fatal(err)
    }
}