how get width and height of Image control - asp.net

Question

I want to change the size of my image in asp.net proportionally, the problem is that I can't get the actual size of the image which is loaded from database. here is the code:
imgAvatar.ImageUrl = "~/Modules/FileViewer.ashx?id=" + o.EventID;
double r = imgAvatar.Width.Value / 300.00;
imgAvatar.Width = new Unit(300, UnitType.Pixel);
imgAvatar.Height = new Unit(imgAvatar.Height.Value / r, UnitType.Pixel);
but the imgAvatar.Width.Value is always 0.0.
what would you suggest to me?

Answer 1

Do not set width and height. The rendered IMG tag will be sized to the size of downloaded image.
However, if the image is too large you might have a problem. In that case, use CSS to set max:
max-width: 300px;
max-height: 300px;
I might have misunderstand the question, considering my answer above. Anyways, the way I see that done would be similar to this:
System.Drawing.Image image = System.Drawing.Image.FromFile(this.Server.MapUrl("~/image path here"));
// sorry if the above line doesn't compile; writing from memory, use intellisense to find these classes/methods
// image.Width and image.Height will work here

Answer 2

Takes the size of the image with Bitmap and calls the below function to resize
Bitmap myBitmap;
string fileName = "foreverAlone.jpg";
myBitmap = new Bitmap(fileName);
Size newSize = NewImageSize(myBitmap.Height, myBitmap.Width, 100);//myBitMap.Height and myBitMap.Width is how you take the original size
Check BitMap class here Bitmap Class - MSDN Article
This code returns new size of the image, and image quality remains the same -no reduce-, FormatSize parameter decides the new size.
public Size NewImageSize(int OriginalHeight, int OriginalWidth, double FormatSize)
{
Size NewSize;
double tempval;
if (OriginalHeight > FormatSize && OriginalWidth > FormatSize)
{
if (OriginalHeight > OriginalWidth)
tempval = FormatSize / Convert.ToDouble(OriginalHeight);
else
tempval = FormatSize / Convert.ToDouble(OriginalWidth);
NewSize = new Size(Convert.ToInt32(tempval * OriginalWidth), Convert.ToInt32(tempval * OriginalHeight));
}
else
NewSize = new Size(OriginalWidth, OriginalHeight);
return NewSize;
}