The image can be anything. It can be jpg, png, anything.
Load it.
Crop it. Say removing first 100 pixels from the left.
Save to the same file
Ref: Graphics.DrawImage and Image Cropping with Image Resizing Using VB.NET
private void btnCropImage_Click(object sender, EventArgs e)
{
OpenFileDialog dlg = new OpenFileDialog();
dlg.ShowDialog();
//check your filename or set constraint on fileopen dialog
//to open image files
string str = dlg.FileName;
//Load Image File to Image Class Object to make crop operation
Image img = System.Drawing.Bitmap.FromFile(str);
// Create rectangle for source image, what ever it's size.
GraphicsUnit units = GraphicsUnit.Pixel;
RectangleF srcRect = img.GetBounds(ref units);
// Create rectangle for displaying image - leaving 100 pixels from left saving image size.
RectangleF destRect = new RectangleF(100.0F, 0.0F, srcRect.Width - 100, srcRect.Height);
// Bitmap class object to which saves croped image
Bitmap bmp = new Bitmap((int)srcRect.Width - 100, (int)srcRect.Height);
// Draw image to screen.
Graphics grp = Graphics.FromImage(bmp);
grp.DrawImage(img, destRect, srcRect, units);
//save image to disk
bmp.Save("e:\\img.jpeg", System.Drawing.Imaging.ImageFormat.Jpeg);
//Clear memory for Unused Source Image
img.Dispose();
}
Hope this help you..