test.cs

string imagePath = "Images/signature1.jpg";

byte[] bytes = File.ReadAllBytes(imagePath);

using (MemoryStream ms = new MemoryStream(
	  bytes, 0, bytes.Length, writable: false, publiclyVisible: true))
{
	// create image object
	TXTextControl.Image myImage = new TXTextControl.Image(ms);
	textControl1.Images.Add(myImage, -1);
}