[Not a question] openfiledialog and picturebox

We do not do your homework: it is set for a reason. It is there so that you think about what you have been told, and try to understand it. It is also there so that your tutor can identify areas where you are weak, and focus more attention on remedial action.

Try it yourself, you may find it is not as difficult as you think!

But, this is a really, really simple task: at it's simplest it's only three lines of code!
1) Create a new OpenFileDialog
2) Use it's ShowDialog method to prompt the user to find the file.
3) Set the PictureBox.Image property to the output of the Image.FromFile method, passing that the FileName property from the OpenFile Dialog.

Do you have any idea what engineering is? This is not "finding", this is doing your job. If everyone would only try to "find any related answer", who would write some code? You need to write code, instead of searching for anything.

So, here is the exact instructions for you: get some time, sit down, and write down the code according to the requirements you just described. There is no "expert knowledge" you might need; everything is written is standard MSDN documentation.

This is just a tiny piece of work. If you are not capable of doing this piece, no "answer" will ever help you, because it would make you seeking for another answer for another tiny piece of work, blocking you from doing any work at all.

—SA