Formula for images by screen resolution?

The Silverlight2 app has 4 images in a grid on the page. I need to set the height, width and margins for each image. These values cannot be constants, because then they will not be displayed correctly for the various possible screen resolutions. These properties should get their values from calculations using only the resolution of the screen. The composite look and feel of these images should be the same regardless of the resolution.
The images are all square, right-aligned and top-aligned, so I only need to set the margins from the top and right (left and bottom margins = 0), and use a single value for height and width.
I use the following to get the resolution:

string Width = Convert.ToString(HtmlPage.Window.Eval("screen.width"));

string Height = Convert.ToString(HtmlPage.Window.Eval("screen.height"));

You could assign a percentage of the screen for each image and then calculate how many pixels correspond to each percentage. I am not sure what you need to do for the width; you could make the width a percentage of the height or a percentage of the screen the same as for the height.

Does that answer your question?

Update: Oooops looks like Frogleg beat me to it. I assume his answer is better than mine.

This help

 public partial class Form1 : Form
{

int deskHeight;
int deskWidth;
double ratio = 0.25;
public Form1()
{
InitializeComponent();
}

private void Form1_Load(object sender, EventArgs e)
{

deskHeight = Screen.PrimaryScreen.Bounds.Height;
deskWidth = Screen.PrimaryScreen.Bounds.Width;
label3.Text = ("Screen resolution = " + Convert.ToString(deskWidth) + " x "+ Convert.ToString(deskHeight));

pictureBox1.Width = Convert.ToInt32((double)deskWidth * ratio);
pictureBox1.Height = Convert.ToInt32((double)deskHeight * ratio);
}
}