Chuyển hình ảnh thành Base64 và ngược lại bằng C# - Convert Image to Base64 and back

Xin chào !
Hôm nay Thi muốn giới thiệu đến các bạn một class C# dùng để chuyển đổi một hình ảnh về dạng base64 và ngược lại. Class này đặt biệt hữu dụng trong trường hợp các bạn muốn chuyển các Object về dạng lưu được để lưu vào xml.
 Ví dụ Thi có hình ảnh sau muôn chuyển sang base64:

Khi chuyển sang base64 sẽ có dạng :
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
Nhúng vào web ta dùng:
<img src="data:image/png;base64,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"/>
Như vậy có thể thấy sự tiện lợi của base64 như thế nào rồi phải không? và class chuyển đổi viết bằng C#.

Giờ thì xin chào.