Google Photos Magic Editor: GenAI Under the Hood of a Billion-User App - Kelvin Ma, Google Photos
Jul 19, 2025 · 20:28
Kelvin Ma, an engineer on Google Photos' editing team, explains how the billion-user app built the Magic Editor by integrating generative AI with on-device computational photography. He traces the evolution from earlier ML features like post-capture segmentation (UNet model, 10 MB) and Magic Eraser (a system of models) to the new server-side generative AI experience, which handles tasks like relocating objects and reimagining backgrounds. Key challenges include managing model size (now hundreds of MB), client-server latency, ambiguous problem scoping (e.g., moving from 5% to 80% reliability), and trust and safety. Ma advocates using evals, reducing ambiguity through product-research collaboration, and iterating from large general models to smaller, faster ones for production. He also highlights that Google Photos serves 1.5 billion monthly active users and processes hundreds of millions of edits per month, and the editor is being rebuilt as AI-first.
