Image in C#: Save, Resize, and Convert to Binary

Sooner or later, you will find the need for handling image in your code, especially when you're working with a database. So in this article, I share with you some useful methods that I find myself using frequently. They include:

• Saving image in a folder
• Getting thumbnail from the original image
• Converting image to binary for saving in database
• Converting binary data back to image

Save an Image

Image originalImage = Image.FromFile(imagePath);
string filePath = AppDomain.CurrentDomain.BaseDirectory + savedName;
originalImage.Save(filePath, System.Drawing.Imaging.ImageFormat.Jpeg);

This code saves the image to the base directory of your app or website. imagePath is the full path to the image that we need to save (e.g. "C:\Pictures\Lighthouse.jpg"), one way to get this is use an OpenFileDialog. savedName is the name for the saved image.

Save the Image as a Thumbnail

public static void SaveImage(string imagePath, string savedName,
    int width = 0, int height = 0)
{
    Image originalImage = Image.FromFile(imagePath);
    string filePath = AppDomain.CurrentDomain.BaseDirectory + savedName;

    if (width > 0 && height > 0)
    {
        Image.GetThumbnailImageAbort myCallback = 
		new Image.GetThumbnailImageAbort(ThumbnailCallback);
        Image imageToSave = originalImage.GetThumbnailImage
			(width, height, myCallback, IntPtr.Zero);
        imageToSave.Save(filePath, System.Drawing.Imaging.ImageFormat.Jpeg);
    }
    else
    {
        originalImage.Save(filePath, System.Drawing.Imaging.ImageFormat.Jpeg);
    }
}
private static bool ThumbnailCallback() { return false; }

Note the parameters: int width = 0 & int height = 0. This is a C# 4.0 feature: Optional Parameters, so we can call this method like this: (assume this method is in the ImageHandling class.)

// Save image as original
ImageHandling.SaveImage(@"C:\Pictures\Lighthouse.jpg", "OriginalLighthouse.jpg");
// Save image as thumbnail
ImageHandling.SaveImage(@"C:\Pictures\Lighthouse.jpg", 
		"ThumbnailLighthouse1.jpg", 160, 90);
// New feature: Named Parameter
ImageHandling.SaveImage(@"C:\Pictures\Lighthouse.jpg", 
		"ThumbnailLighthouse2.jpg", height: 90, width: 160);

Resize the Image and Keep Aspect Ratio

int newWidth = originalImage.Width * percentage / 100;
int newHeight = originalImage.Height * percentage / 100;

To keep the image aspect ratio, simply replace width & height parameters with percentage parameter and call the GetThumbnailImage method with our new width & height.

Convert Image to Binary

public static byte[] ImageToBinary(string imagePath)
{
    FileStream fileStream = new FileStream(imagePath, FileMode.Open, FileAccess.Read);
    byte[] buffer = new byte[fileStream.Length];
    fileStream.Read(buffer, 0, (int)fileStream.Length);
    fileStream.Close();
    return buffer;
}

Use this method when you want to save images in your database. The column to store binary data is usually varbinary(MAX).

Convert Binary to Image

You store images in your database as binary, of course you must convert binary back to images so you can display them in your app.

public static Image BinaryToImage(System.Data.Linq.Binary binaryData)
{
    if (binaryData == null) return null;

    byte[] buffer = binaryData.ToArray();
    MemoryStream memStream = new MemoryStream();
    memStream.Write(buffer, 0, buffer.Length);
    return Image.FromStream(memStream);
}

You may need to add reference to System.Data.Linq. LINQ-to-SQL maps a varbinary column in your database to its relevant property as System.Data.Linq.Binary.

What about you? What are your favorite image-handling functions? Are there any other functions you'd like to have?

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