base64转换为图片

package main

import (
	"encoding/base64"
	"io/ioutil"
	"os"
	"strings"
)

func main() {
	cc, _ := ioutil.ReadFile("a.png.txt")
	//解压
	i := strings.Index(string(cc), ",")
	cc = cc[i+1:]
	dist, _ := base64.StdEncoding.DecodeString(string(cc))
	//写入新文件
	f, _ := os.OpenFile("b.png", os.O_RDWR|os.O_CREATE, os.ModePerm)
	defer f.Close()
	f.Write(dist)

}

　a.png.txt

data:image/png;base64,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