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Saving cropped image (displayed in another picturebox as graphics) locally

This is the scenario, Suppose I have two pictureboxes. pbSrc displaying the Source Image and pbCrop displaying the cropped image. My code below shows the cropped of image from pbSrc to pbCrop. I tried saving it but the output was not as what I was expecting it to be :((((
pbCrop.Refresh();
//Prepare a new Bitmap on which the cropped image will be drawn
Bitmap sourceBitmap = new Bitmap(pbSrc.Image, pbSrc.Width, pbSrc.Height);
Graphics a = pbCrop.CreateGraphics();
//Draw the image on the Graphics object with the new dimesions
a.DrawImage(sourceBitmap, new Rectangle(0, 0, pbCrop.Width, pbCrop.Height), rectCropArea, GraphicsUnit.Pixel);
a.Save(); //Not sure if this really does saves the image into a file :v

What's the best way to clip a bitmap using its inscribed ellipse

I'd like to take a bitmap with an ARGB 32 pixel format and clip it so that the contents within its inscribed ellipse remain, and anything outside the ellipse turns into ARGB(0,0,0,0).
I could do it programmatically using GetPixel and SetPixel and some trigonometry to figure out which pixel is out of bounds - but I suspect there's a better, more built-in way to do it.
Any ideas?

Thanks to Alessandro D'Andria for pointing out the region part - I've figured out the rest:
public Bitmap Rasterize()
{
Bitmap ringBmp = new Bitmap(width: _size.Width, height: _size.Height, format: PixelFormat.Format32bppArgb);
//Create an appropriate region from the inscribed ellipse
Drawing2D.GraphicsPath graphicsEllipsePath = new Drawing2D.GraphicsPath();
graphicsEllipsePath.AddEllipse(0, 0, _size.Width, _size.Height);
Region ellipseRegion = new Region(graphicsEllipsePath);
//Create a graphics object from our new bitmap
Graphics gfx = Graphics.FromImage(ringBmp);
//Draw a resized version of our image to our new bitmap while using the highest quality interpolation and within the defined ellipse region
gfx.InterpolationMode = Drawing2D.InterpolationMode.NearestNeighbor;
gfx.SmoothingMode = Drawing2D.SmoothingMode.HighQuality;
gfx.PixelOffsetMode = Drawing2D.PixelOffsetMode.HighQuality;
gfx.PageUnit = GraphicsUnit.Pixel;
gfx.Clear(Color.Transparent);
gfx.Clip = ellipseRegion;
gfx.DrawImage(image: _image, rect: new Rectangle(0, 0, _size.Width, _size.Height));
//Dispose our graphics
gfx.Dispose();
//return the resultant bitmap
return ringBmp;
}
Apparently it is extremely important to set PixelOffsetMode to HighQuality, because otherwise the DrawImage method would crop parts of the resulting image.

Don't scale image when creating new bitmap from existing image

Does anyone know how to create a new bitmap from an existing image with a taller height, but don't scale the image and just have transparent, black or white below the original image in the new bitmap?
I basically have one picture that is taller than the second and I need the second one to be as tall as the first, without stretching it.
img2 = new Bitmap(lImages[2],new Size(pictureBox.Image.Width,pictureBox.Image.Height));
img2 = ((Bitmap)img2).Clone(new Rectangle(0, 0, pictureBox.Image.Width, pictureBox.Image.Height), System.Drawing.Imaging.PixelFormat.Format24bppRgb);
C# .NET 4.0.

By using a Graphics object, you can achieve this easily:
Bitmap temp = new Bitmap(new Size(pictureBox.Image.Width,pictureBox.Image.Height));
using(Graphics g = Graphics.FromImage(temp))
{
g.DrawImage(img2, 0, 0);
}
img2 = temp;
Now img2 references a new Bitmap object of the required size which has the original (unstretched) image painted on it.
Note: To control the color of the extra space, add a call to g.FillRect before drawing the image.

Create your "standart" size bitmap and fill it with, let's say, white color and call Bitmap.MakeTransparent(Color.White) and draw your final image over it.

Repeating the image in horizontal position ( C# Drawing )

am using c#
am having a bitmap image like below
i want create a repeated image like below in horizontal position to get repeted continous image for some given width. i meant i like to draw repeated image like below from the above single bitmap (In simple words,in html we can have a image and set repeat X to get the repeated image.like that) how i can do this in c#.
so that i can draw a new bitmap in my application. How to do this.?

//x- integer value represents no. of times images to repeated horizontally
var destImage = new Bitmap(sourceImage.Width * x, sourceImage.Height, PixelFormat.Format32bppArgb);
using (TextureBrush brush = new TextureBrush(sourceImage, WrapMode.Tile))
using (Graphics g = Graphics.FromImage(destImage))
{
// Do your drawing here
g.FillRectangle(brush, 0, 0, destImage.Width, destImage.Height);
destImage.Save(#"C:\sourceImage.png", ImageFormat.Png);
//mention path of image to save, if needed
}

You can do it like this:
Bitmap myImage = new Bitmap(50, 50); //assuming you want you image to be 50,50
Bitmap originalImage = new Bitmap("myPngSource.png"); //original image to copy
using (Graphics g = Graphics.FromImage(myImage))
{
g.DrawImage(originalImage, new Rectangle(0, 0, originalImage.Width, originalImage.Height));
}
MemoryStream ms = new MemoryStream();
myImage.Save(ms, ImageFormat.Png);
BitmapImage bi = new BitmapImage();
bi.BeginInit();
bi.StreamSource = ms;
bi.EndInit();
MyImageControl.Source = bi;
Or something like that, this is untested, and I just ripped it out of a little utility app I made a while ago. I hope it helps... You just need to change the width of the final image and do a loop over the g.DrawImage call incrementing the second parameter by the width of the originalImage. (i.e. if you want 5 repeats, do a for loop 5 times)
HTH
--Mark

you don't need to create other bitmaps. it's a matter of drawing bitmap. in the place you darw the bitmap use
drawImage method few times and increment the X position of the bitmap by its width. say 16 is the width of your image. make sure that bitmap has been initialized.
private void Form1_Paint(object sender, PaintEventArgs e)
{
e.Graphics.DrawImage(bmp,x,y);
e.Graphics.DrawImage(bmp,x+16,y);
e.Graphics.DrawImage(bmp,x+32,y);
}

Can i add watermark on a series of pictures?

I have a strong amount of pictures, which i would like to "protect" by adding watermark on them. Is there any way of adding watermark by using vb.net or C# ?

public void AddWatermark(string filename, string watermarkText, Stream outputStream) {
Bitmap bitmap = Bitmap.FromFile(filename);
Font font = new Font("Arial", 20, FontStyle.Bold, GraphicsUnit.Pixel);
Color color = Color.FromArgb(10, 0, 0, 0); //Adds a black watermark with a low alpha value (almost transparent).
Point atPoint = new Point(100, 100); //The pixel point to draw the watermark at (this example puts it at 100, 100 (x, y)).
SolidBrush brush = new SolidBrush(color);
Graphics graphics = null;
try {
graphics = Graphics.FromImage(bitmap);
} catch {
Bitmap temp = bitmap;
bitmap = new Bitmap(bitmap.Width, bitmap.Height);
graphics = Graphics.FromImage(bitmap);
graphics.DrawImage(temp, new Rectangle(0, 0, bitmap.Width, bitmap.Height), 0, 0, bitmap.Width, bitmap.Height, GraphicsUnit.Pixel);
temp.Dispose();
}
graphics.DrawString(text, font, brush, atPoint);
graphics.Dispose();
bitmap.Save(outputStream);
}

Use ImageMagick with the .Net wrapper.

This blog post promises:
This article shall describe an approach to building a simple watermarking utility that may be used to add watermarks to any supported image file format. The resulting application shall permit the user to open any supported image file format into a scrollable picture box, to define the text to be applied as a watermark (with a default version supplied), to set the font and color of the watermark, to define the opacity of the watermark, to determine whether or not the watermark appears at the top or bottom of the image, and to preview the watermark prior to saving it to the image.
It should provide a good starting point.