This article explains how to add a picture to a contact in Gmail. Instructions apply to the web version of Gmail and Google Contacts, and should work in any web browser, including Google Chrome, Microsoft Edge, and Mozilla Firefox.
How to: Add an image to a signature in Gmail
To set a photo for a Gmail contact:
Open a web browser, go to Gmail and sign in.
Go to the top right corner of the Gmail screen and select the Google Apps icon.