Graphics graph = null;
var bmp = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height);
graph = Graphics.FromImage(bmp);
graph.CopyFromScreen(0, 0, 0, 0, bmp.Size);
var ms = new MemoryStream();
bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
string convertedImg = Convert.ToBase64String(ms.ToArray(), Base64FormattingOptions.None);<img alt="" src="data:image/png;base64, CONVERTED_BASE64"/>
Bitmap printscreen = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height);
Graphics graphics = Graphics.FromImage(printscreen as Image);
graphics.CopyFromScreen(0, 0, 0, 0, printscreen.Size);
var ms = new MemoryStream();
printscreen.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
string convertedImg = Convert.ToBase64String(ms.ToArray(), Base64FormattingOptions.None);/9j/4AAQSkZJRgABAQEAYABgAAD/2wBDAAgGBgcGBQgHBwcJCQgKDBQNDAsLDBkSEw8UHRofHh0aHBwgJC4nICIsIxwcKDcpLDAxNDQ0Hyc5PTgyPC4zNDL/2wBDAQkJCQwLDBgNDRgyIRwhMjIyMjIyMjIyMjIyMjIyMjIyMjIyMjIyMjIyMjIyMjIyMjIyMjIyMjIyMjIyMjIyMjL/wAARCAMABVYDASIAAhEBAxEB/8QAHwAAAQUBAQEBAQEAAAAAAAAAAAECAwQFBgcICQoL/8QAtRAAAgEDAwIEAwUFBAQAAAF9AQIDAAQRBRIhMUEGE1FhByJxFDKBkaEII0KxwRV... и т.д.<img alt="" src="data:image/png;base64,ТУТ_ПРОБЕЛА_У_ВАС CONVERTED_BASE64"/>
Простой
Простой
Простой
Простой