Q: Saving Images in a folder using for loop I want to save images in a folder C:\Users\crowds\Documents\Example using a for loop. 
and I want also the name to save like this:
Sample.jpg, Sample1.jpg
Any idea how can I implement it?
Here's my code snippet:
private void button4_Click(object sender, EventArgs e)
    {
        var capture = new Emgu.CV.Capture();

        using (var ImageFrame = capture.QueryFrame())
        {
            if (ImageFrame != null)
            {
                pictureBox1.Image = ImageFrame.ToBitmap();
                ImageFrame.Save(@"C:\Users\crowds\Documents\Example\Sample.jpg");

            }
            _capture.Dispose();
        }


A: You could try this something like this:
List<Image> imageList = //Get all the image list
for(i=0; i<imageList.Count;i++) 
 { 
   ImageFrame.Save(@"C:\Users\crowds\Documents\ExampleSample"+i.toString()+".jpg");           
 }


A: try it 
string root="C:\Users\crowds\Documents\Example\Sample";
for(int i=0;i<value;i++)
{ 
    string path=root+i+".jpg"; ImageFrame.Save(path);
}

and better debug more.

A: Based on your comment if you simply want to just save to a different filename each time you could do something like:
private int filenumber = 0;

private void button4_Click(object sender, EventArgs e)
{   
    using (var capture = new Emgu.CV.Capture())
    using (var ImageFrame = capture.QueryFrame())
    {
        if (ImageFrame != null)
        {
            pictureBox1.Image = ImageFrame.ToBitmap();
            ImageFrame.Save(String.Format(@"C:\Users\crowds\Documents\Example\Sample{0}.jpg", filenumber++));       
        }   
    }
}

Note that this code just not check of the pre-existence of a file and may throw an Exception if it already exists. Ideally you should check first using File.Exists(...)

A: The EMGU CV library creates a capture image from the capture device and then you manage it however you like.  Your example is attempting to save an image on a button press and is not iterating through a collection of images.
What you might want to look into is a counter mechanism that you maintain.  For example either when you press your button, or at application initialisation, you read the directory containing your images and parse the names to determine the name of the last image saved.  Obtain the number part of the image name and use that to initialise your counter, then each time your button is pressed to save an image, increment the counter.
A simplified example below:
Counter
private int lastSaveCount = 0;

This needs to be somewhere both your Button_Click event and the Initialise Counter mechanism below can access.
Initialise Counter
var files = Directory.GetFiles(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments) + @"\Example\", @"Sample*.jpg").ToList();
foreach (var file in files)
{
    var split = Regex.Split(file, @"[a-zA-Z]{1,}([\d]{1,}).jpg", RegexOptions.IgnoreCase);
    var save = 0;
    if (Int32.TryParse(split[1], out save))
    {
        lastSaveCount = save > lastSaveCount ? save : lastSaveCount;
    }
}

Place the above somewhere appropriate.
Button Press
private void button4_Click(object sender, EventArgs e)
{
    var capture = new Emgu.CV.Capture();

    using (var ImageFrame = capture.QueryFrame())
    {
        if (ImageFrame != null)
        {
            lastSaveCount++;
            pictureBox1.Image = ImageFrame.ToBitmap();
            var filename = string.Format(@"C:\Users\crowds\Documents\Example\Sample{0}.jpg", lastSaveCount);
            ImageFrame.Save(filename);

        }
        _capture.Dispose();
    }
}

