Well, before you answer hastily or ponder too much, let me tell you that you can make Gmail display any image for any contact. Others can "suggest" a picture to be displayed (as can you), but you can override this easily.
Once a contact has been assigned a picture, you can see it whenever you position the mouse over an email address or name.
Add an Image to a Contact in Gmail
To set up a picture for a Gmail contact:
- Go to Contacts.
- Search for and click on the desired contact.
- Click Add a picture.
- Use My Computer, Picasa Web Album or Web Address (URL) to choose the desired image.
- Click Select Image.
- Crop the image if needed.
- Click Apply Changes.
Add an Image to a Contact in Gmail (Older Version)
To assign a picture to a contact in Gmail's older version:
- Follow the Contacts link in Gmail.
- Click on the desired contact's name.
- Now click Edit contact information.
- Make sure My pick is selected under Picture:.
- Click upload picture.
- Use the Browse... button to select the desired image.
- Click Upload picture ».
- Highlight the desired frame.
- Click the Crop picture » button.
- Click Save.