Image Formats for Mobile Apps: iOS and Android Guide

Mobile apps (iOS and Android) have different image requirements than web. Storage constraints, screen densities, and app store rules create unique optimization challenges.

iOS Image Formats

iOS supports JPEG, PNG, HEIC, and WebP (iOS 14+). HEIC is native and preferred for high quality and small size. App store prefers PNG/JPEG for UI.

iOS Resolution (Density)

Provide three resolutions: 1x, 2x (retina), 3x (iPhone 14+). Name files @2x and @3x. iOS loads the right version automatically.

Android Image Formats

Android supports JPEG, PNG, WebP, and HEIC (Android 10+). WebP is recommended for photos. PNG for graphics.

Android Resolution (DPI Buckets)

Provide images for ldpi, mdpi, hdpi, xhdpi, xxhdpi, xxxhdpi buckets. Or use Vector Drawables (SVG-like) for density independence.

App Bundle Optimization

Google Play requires App Bundles for new apps. Google automatically provides device-specific APKs. Optimize images for each DPI; users download only what they need.

Storage Constraints

Apps download and install. Every MB counts. Compress aggressively. HEIC on iOS, WebP on Android saves 30–50% vs JPEG.

Memory Constraints

Old phones have limited RAM. Load and decode large images carefully. Use thumbnail grids, lazy load full images on tap.

Color Space

Use sRGB. Both iOS and Android default to sRGB. Wider color spaces are not beneficial and add complexity.

Optimization Pipeline

Create master images. Generate 1x, 2x, 3x versions. Convert to optimal format per platform (HEIC for iOS, WebP for Android). Include in app bundle.

Best Practices

Use vector graphics (SVG or PDF) for UI icons. Use compressed rasters (JPEG/WebP/HEIC) for photos. Lazy load below-the-fold images. Compress aggressively without visible quality loss.