If your in-app message image appears too small, compressed, or pixelated on Android or iOS devices, the image resolution is likely insufficient for full-screen display scaling. Mobile in-app messages require significantly higher image resolution than web email or standard digital media.
What causes this
Mobile in-app messaging systems automatically scale images to fit screen dimensions while maintaining aspect ratios. When a low-resolution image — such as 361x720 pixels — is used, the system scales it up to fill modern mobile screens (typically 1080x1920 pixels or higher), resulting in visible pixelation or a smaller displayed size than expected.
The image may appear acceptable during template preview but renders poorly when delivered to actual devices, because the rendering engine prioritizes maintaining image quality over filling available screen space.
How to fix it
Use higher-resolution images when creating in-app message templates:
- Full-screen in-app messages: Use a minimum resolution of 1080x1920 pixels. This ensures images scale properly across virtually all modern Android and iOS device sizes without quality degradation.
- Smaller or centered images: Use at least 800x1000 pixels to maintain quality when scaled to mobile screens.
When creating or sourcing images for in-app templates:
- Export or capture at 1080x1920 pixels or higher
- If using graphic design software, set your canvas to these dimensions before creating artwork
- Test your in-app message on both Android and iOS devices with various screen sizes — using actual devices or an emulator — before launching campaigns
Related documentation
For complete design specifications and best practices, refer to the Acoustic Mobile Developer documentation: Best practices for customizing mobile app messages.