In one sentence, describe what the following article is about:

The add photo button looks different on different phone operating systems. Touch the image placeholder button. In order to add a profile photo, you'll need a working Internet connection. On iPhone, touch OK to give WhatsApp access to your photos.  If you have a touchscreen phone, use your fingers to move the image inside the circle. Pinch and zoom to change the image's size.

Summary:
Use an existing image as a profile photo. Touch choose existing or upload photo button. Choose a profile photo. Move and scale the image. Touch the choose or done button to select the image.