How to get image in specified size given in parameter?

you can use the following function to re-size the image

public Image ImageResize(Image image, int width, int height)
{
     Bitmap newImage = new Bitmap(width, height);
     using (Graphics gr = Graphics.FromImage(newImage))
     {
            gr.SmoothingMode = SmoothingMode.AntiAlias;
            gr.InterpolationMode = InterpolationMode.HighQualityBicubic;
            gr.PixelOffsetMode = PixelOffsetMode.HighQuality;
            gr.DrawImage(image, new Rectangle(0, 0, width, height));
     }
     return newImage as Image;
}

and to display the image

1- use the asp image tag

<asp:Image id="imageTag" runat="server"/>

2- save the Image to a folder by the following Image temp=ImageResize(YourImage,200,200);

temp.SaveAs(MapPath("~/Images/image1.png"));

3- map the image url to the path

imageTag.ImageUrl=Server.MapPath("~/Images/image1.png");

another approach, is to use the ashx handler if you insist to use <img>, but at the end , asp:Image will be rendered as <img>

Edited Here

how to get the image resized using ashx

1- create a generic handler and name it ImageHandler

 public class ImageHandler : IHttpHandler
    {

        public void ProcessRequest(HttpContext context)
        {
            var directory = @"Location of the images" // example c:\Data;
            var path = context.Request.QueryString["path"];
            var size = Convert.ToInt32(context.Request.QueryString["size"]);
            var image = Image.FromFile(string.Format(@"{0}\{1}.png", directory, path));
            image = ImageResize(image, size, size);
            context.Response.ContentType = "image/png";
            context.Response.BinaryWrite(ImageToByte(image));
        }

        public Image ImageResize(Image image, int width, int height)
        {
            Bitmap newImage = new Bitmap(width, height);
            using (Graphics gr = Graphics.FromImage(newImage))
            {
                gr.SmoothingMode = SmoothingMode.AntiAlias;
                gr.InterpolationMode = InterpolationMode.HighQualityBicubic;
                gr.PixelOffsetMode = PixelOffsetMode.HighQuality;
                gr.DrawImage(image, new Rectangle(0, 0, width, height));
            }
            return newImage as Image;
        }

        public byte[] ImageToByte(Image img)
        {
            byte[] byteArray = new byte[0];
            using (MemoryStream stream = new MemoryStream())
            {
                img.Save(stream, System.Drawing.Imaging.ImageFormat.Png);
                stream.Close();

                byteArray = stream.ToArray();
            }
            return byteArray;
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }

2- in the aspx page, use the following

<img src="~/ImageHandler.ashx?path=NameOfImage&size=SizeOfImage" runat="server" />

hope this will help you

regards