5.) Why is there a timeout on slideshows?
Google Photos imposes a global limit on the number of items that can be downloaded in a 24-hour period within the PhotoView app. This limit collectively applies to all users of the application, so we’re talking in the ten’s of millions of downloads per day. We impose a time limit to reduce a screensaver running for many hours with no one viewing, so we can better allocate downloads to active users. Currently, this timeout expires after 12-hours, but you can easily start it again to continue viewing.
Starting with v3.7, if your album is rotating through 20 images or less, the timeout is ignored. This is due to images being pulled from your device’s local cache. Pulling from local cache means it doesn’t impact our daily limit from Google. Enjoy!