No, phones do not store fingerprints as images. Instead, they store a mathematical representation, or a hash, of your fingerprint's unique features. This means a simplified, encrypted version of your fingerprint's characteristics is saved, not an actual picture.
How Fingerprint Data is Stored
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Mathematical Representation: Your phone's fingerprint scanner doesn't save a photo of your fingerprint. Instead, it analyzes unique features and creates a mathematical formula representing these features. This formula is what's actually stored. [Reference: Multiple sources including Quora, Reddit, and StackExchange posts confirm this method.]
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Secure Storage: This mathematical representation is typically stored in a secure location within the phone's hardware, often called a Trusted Execution Environment (TEE). This isolated area protects your fingerprint data from unauthorized access. [Reference: NEC New Zealand's article on biometric data storage.]
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No Cloud Storage (Generally): Reputable phone manufacturers like Google explicitly state that your fingerprint data is not shared with them or stored in the cloud. [Reference: Reddit post mentioning Google's statement regarding Pixel and Nexus phones.]
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Limited Storage Capacity: Phones often have a limit on the number of fingerprints they can store. This is not due to storage limitations, but rather security considerations and to avoid performance issues. [Reference: StackExchange post discussing limits on fingerprint storage on Android.]
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Comparison, Not Image Matching: The scanner doesn't compare a scanned fingerprint to a stored image; it generates a new mathematical representation and compares it to the stored one. This comparison confirms or denies a match. [Reference: Jetholt's article on Samsung phone fingerprint limits.]
Different Operating Systems & Manufacturers
While the core principle remains consistent, specific implementations may vary slightly between Android and iOS devices or different manufacturers. However, the general approach of storing a mathematical representation rather than an image is prevalent across the industry. [Reference: Apple Support pages on Touch ID confirm that no images are stored.]
