Make PictureBox invisible when I type text in a textBox

Question

Hi:

A simple Question. I am new to Visual C#.
I have a PicutreBox control visible on a form.
I have a textBox control  on the same form.
when I start entering the text in the textBox,
I want the PictureBox to disappear.

Could you please let me know how to do this.

Thanks for your help.
Regards,
bsoo