Add a photo for a contact on iCloud.com
You can add or change a photo for a contact. The photo appears in all features that share your iCloud Contacts information. You can change the photo at any time.
In Contacts on iCloud.com, select a contact.
Double-tap the photo or the people icon next to the contact’s name.
Tap Choose Photo, then follow the onscreen instructions.
To resize the photo, drag the slider below the photo.
You can also add a photo when you add a new contact.
For information about photo file types and size limits, see the Apple Support article Limits for iCloud Contacts, Calendars, Reminders, and Bookmarks.