There are many ways to specify HTML color codes in C#. The .net framework has a great object for dealing with colors called Color. Here are some of the ways that you can create a Color object.
C# Source Code Example to Modify Color
// if you have an HTML string var lightGray = System.Drawing.ColorTranslator.FromHtml("#D3D3D3"); // if you have 3 hex numbers var lightGray = System.Drawing.Color.FromArgb(0xD3, 0xD3, 0xD3); // you can specify known color names var lightGray = Color.LightGray; // if you want to specify an alpha (transperancy) you can use FromArgb // the first int is the transperancy. 255 is solid while 0 is fully transperant var lightGray = Color.FromArgb(255, 0xD3, 0xD3, 0xD3); // you can also use integers with FromArgb var lightGray = Color.FromArgb(255, 211, 211, 211); // if you are using WPF and you want to specify an alpha in HTML style you can do this using System.Windows.Media; var lightGray = (Color)ColorConverter.ConvertFromString("#FFD3D3D3");
All of these methods will generate the same Color object and you can use any of them as you see fit.
C# Color Object
The C# Color object is very useful and has some great properties. We have a guide to help you make use of it.
C# Image Processing
We have many more articles about C# Image Processing that you might want to check out - C# Image Processing.