I've noticed that contact photos on the iPhone seem to appear in one of two modes:
- Thumbnail: A small square image shown next to the contact's name or number
- Full-Screen: The image takes up the entire display, overlaid by the caller ID and Swipe-to-answer controls
How the phone determines which mode to use isn't terribly clear. This question, for example, dealing with contact syncing, seems to have people experiencing different results depending on whether they set the photo on the phone, synced from Gmail, synced from iCloud, etc.
Does anyone know the canonical rules for when a contact image appears in full-screen or as a thumbnail? Is it related to image size / shape, or only to the source of the image?