Take a source image (jpg/png) and output a base64 encoded html <img> png

main.go

package main

import (
	"bytes"
	"encoding/base64"
	"fmt"
	"image"
	_ "image/jpeg"
	"image/png"
	"log"
	"os"

	"github.com/nfnt/resize"
)


func main() {
   	resizedImg := resize.Resize(200, 200, decodeImage("source.png"), resize.Lanczos3)
	var buf bytes.Buffer
	if err := png.Encode(&buf, resizedImg); err != nil {
		log.Fatal("Error encoding png for base64", err)
	}

	encodedStr := base64.StdEncoding.EncodeToString(buf.Bytes())
	fmt.Print("<img src=\"data:image/png;base64, ", encodedStr, "\" />")
}

func decodeImage(filepath string) image.Image {
    f, err := os.Open(filepath)
    if err != nil {
        log.Fatalf("Failed to open source")
    }

    img, _, err := image.Decode(f)
    if err != nil {
        log.Fatal("Failed to decode image: ", err)
    }

    if err := f.Close(); err != nil {
        log.Fatal(err)
    }

    return img
}