DocumentationExperience Cloud KCS

Dynamic Media: Inconsistent image format fallback and transparency loss on iPhone

Last update: October 9, 2026

This article explains how to troubleshoot and resolve issues where Dynamic Media delivers inconsistent image formats for PNG and GIF assets on iPhone devices, resulting in loss of transparency or animation.

Description description

Environment

  • Dynamic Media
  • iPhone devices
  • PNG and GIF assets
  • AVIF image delivery

Issue/Symptoms

  • When accessing image assets through Dynamic Media URLs with an .avif extension from iPhone devices, some PNG and GIF assets may be delivered in JPEG format instead of the expected fallback format.
  • PNG and GIF transparency may be lost when the asset is delivered as JPEG.
  • GIF animation may also be lost.
  • When AVIF is not supported by the device or browser, the expected behavior is for Dynamic Media to fall back to PNG for PNG assets and GIF for GIF assets, preserving transparency and animation.
  • The fallback behavior may be inconsistent, resulting in some assets being served as JPEG, which does not support transparency or animation.

Resolution resolution

Follow the steps below to resolve the issue:

  1. Test asset delivery by accessing the Dynamic Media asset URL with an .avif extension from an iPhone device or simulator. Inspect the delivered image format by checking the response headers or downloading the image.
  2. Clear the browser cache by testing in an incognito or private browsing window if you observe the asset being delivered as JPEG after a recent change. This avoids cached responses.
  3. For PNG assets, if transparency is lost (that is, the asset is delivered as JPEG), verify that your Dynamic Media environment is up to date. If the issue persists, collect the affected asset URLs and reproduction steps for further troubleshooting.
  4. For GIF assets, use the original asset endpoint with the .gif extension to preserve animation and transparency. Requesting GIF assets through an .avif URL may not correctly fall back to GIF. Use the original endpoint for reliable GIF delivery.
  5. If issues persist, monitor Adobe release notes or support channels for updates regarding fallback behavior for GIF assets.
  6. After making changes or using the recommended endpoints, verify that the delivered assets retain transparency for PNG and GIF assets and animation for GIF assets on iPhone devices.
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