换个姿势访问图片

using System.Drawing;
using System.Web;
using cczcrv.Web.File.Uploader.Image;
using System.IO;

namespace cczcrv.Web.File.Filters
{
    public class GetImageHandler : IHttpHandler
    {
        public void ProcessRequest(HttpContext context)
        {
            //图片不存在，返回默认图片
            var path = context.Server.MapPath(context.Request.Url.AbsolutePath);
            if (!System.IO.File.Exists(path))
            {
                CreateImageResponse(context, "");
                return;
            }

            int width = 0;
            var strWidth = context.Request.Params["width"];
            if (!string.IsNullOrWhiteSpace(strWidth) && int.TryParse(strWidth, out width))
            {
                var index = path.LastIndexOf(‘\\‘);

                //缩略图目录不存在，创建目录
                var thumbnailDirectory = $"{path.Substring(0, index)}/thumb_{width}";
                if (!Directory.Exists(thumbnailDirectory))
                {
                    Directory.CreateDirectory(thumbnailDirectory);
                }
                var thumbnailPath = $"{thumbnailDirectory}/{path.Substring(index + 1)}";
                //缩略图不存在，生成缩略图
                if (!System.IO.File.Exists(thumbnailPath))
                {
                    var image = Image.FromFile(path);

                    //width大于图片本身宽度，则返回原图
                    if (width >= image.Width)
                    {
                        CreateImageResponse(context, path);
                        return;
                    }
                    ThumbnailHelper.MakeThumbnail(image, thumbnailPath, width, 100, ThumbnailModel.W);
                }
                CreateImageResponse(context, thumbnailPath);
                return;
            }
            CreateImageResponse(context, path);
        }

        public bool IsReusable { get { return false; } }

        #region 私有方法

        /// <summary>
        /// 返回图片
        /// </summary>
        /// <param name="context">当前上下文</param>
        /// <param name="filePath">图片路径</param>
        private void CreateImageResponse(HttpContext context, string filePath)
        {
            context.Response.ContentType = "image/JPEG";
            context.Response.WriteFile(filePath);
            context.Response.End();
        }

        #endregion

    }
}

<add name="getImage" path="/upload/image/*" verb="GET" type="cczcrv.Web.File.Filters.GetImageHandler" />