Media files may take time to sync
Recent Anki and AnkiMobile versions synchronize sounds and images in the background, allowing you to continue using the app while they are transferred. Until the media files have been transferred, audio may fail to play, and images may fail to appear if those files are not available yet.
If you tap on the sync button when a spinner is shown next to it, it will reveal more details about the syncing progress. If you are waiting for sounds/images to start working, please wait for that window to show "media sync complete". Once that message has been displayed, it indicates all media files have been transferred to or from your device, and the media should then work during study.
If your device's screen is turned off or you switch to a different app, it will interrupt the sync. When you sync again, the download will resume. Your device's auto-lock will also interrupt the sync, so if you wish to leave your device to download, please go to iOS's settings screen, and temporarily turn off auto lock in the display preferences.
If sounds or images fail to appear after "media sync complete" is shown, please check that you have syncing of sounds and images enabled in the preferences screen, and please use the "Check Media" function in the preferences screen or tools menu to check if you are missing files.