图片jpg,png转为BASE64编码

--

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;

namespace aliyun.utils
{
    public static class ImageUtil
    {
        /// <summary>
        /// 将图片数据转换为Base64字符串,(默认是JPEG)
        /// </summary>
        public static string ToBase64(string filename)
        {
            ImageFormat imgf = System.Drawing.Imaging.ImageFormat.Jpeg;
            using (Image img = Image.FromFile(filename))
            {
                using (MemoryStream memStream = new MemoryStream())
                {
                    img.Save(memStream, imgf);
                    byte[] bytes = memStream.GetBuffer();
                    string base64 = Convert.ToBase64String(bytes);
                    return base64;
                }
            }
        }

    }
}

--