React Native<Image> core trong RN có cache rất cơ bản: iOS dùng NSURLCache (limit 20MB default), Android dùng OkHttp memory cache. Không có disk cache mạnh, không có placeholder/blur, không có priority queue. Hậu quả: list ảnh lớn → reload từ network khi user scroll lên/xuống nhiều lần, RAM spike.
expo-image (recommended 2026):
- Dùng SDWebImage (iOS) + Glide (Android) bên dưới — cache mạnh, disk + memory.
- Hỗ trợ placeholder (blurhash, thumbnail), transition, contentFit (như CSS object-fit).
- Hỗ trợ format mới: AVIF, WebP, GIF, animated WebP.
- Cài qua Expo (dùng được cả bare workflow).
react-native-fast-image (lib cũ hơn): cũng dùng SDWebImage/Glide, có priority/headers/cache control. Maintain chậm dần khi expo-image phổ biến.
Khi nào dùng image core: ảnh local nhỏ (icon, logo). Khi nào nâng cấp: bất kỳ list/feed/gallery có ảnh remote >50 items, hoặc cần placeholder để chống layout shift.
RN core <Image> has very basic caching: iOS uses NSURLCache (default 20 MB cap), Android uses OkHttp's memory cache. There is no strong disk cache, no placeholder/blur, no priority queue. Result: a large image list reloads from the network when the user scrolls back and forth, with RAM spikes.
expo-image (recommended 2026):
- Uses SDWebImage (iOS) + Glide (Android) under the hood — strong disk + memory cache.
- Supports placeholder (blurhash, thumbnail), transition, contentFit (like CSS object-fit).
- Modern formats: AVIF, WebP, GIF, animated WebP.
- Installs via Expo (also works in bare workflow).
react-native-fast-image (older library): also uses SDWebImage/Glide, with priority/headers/cache controls. Maintenance has slowed as expo-image takes over.
When the core component is fine: small local assets (icons, logos). When to upgrade: any list/feed/gallery with >50 remote images, or whenever you need a placeholder to prevent layout shift.