How to detect Specific Rectangle from many rectangles using visual studio? and Crop automatically on the next picture box

This is very vague: what does the picture on the right covered in black represent ? There's all kinds of "rectangles" in that image: which kind of rectangle do you want to locate: exactly do you mean by "rectangle" ? What information do you have that determines how you find the rectangle you want to crop to in the second image ?

Remember we can't read your screen, or your mind :)