Floating overlays and
battery — the real cost.
Any app that draws over other apps gets blamed for battery drain, usually before anyone measures it. The honest answer depends on what the overlay is actually doing between the moments you see it, and on a piece of Android called Doze.
What actually costs battery on Android
Three things dominate: the screen, the radios, and the CPU staying awake. An overlay that renders a still image for a few seconds and then stops touching the screen contributes to none of them in any sustained way. What costs battery is an app that holds a wake lock, polls a network, or keeps a service running at high priority around the clock.
Bubbles In Time works offline. There is no server, no account and no sign-up — your photos never leave your phone, so there is no network polling to pay for.
How Doze changes the picture
Since Android 6.0, Doze suspends most background work when the phone has been stationary, screen off, and unplugged for a while. Deferred jobs batch into maintenance windows instead of firing whenever they like. That is why the biggest battery question for any ambient app is not "how often does it appear" but "what is it doing while the screen is off." The answer for a photo overlay should be: nothing.
Frequency and what it costs
A photo that appears every thirty minutes wakes the display path far less than a messaging app you check twenty times an hour. Longer intervals cost less, but the difference between a thirty-minute and a four-hour interval is smaller than most people expect, because the expensive part is the screen being on at all — and if you are looking at your phone, the screen is already on.
Bubbles In Time runs on Android 7.0 and up, costs $2.99 once, and has no subscription, no ads and no in-app purchases.
How to check it yourself
Android reports this without any special tools. Open Settings → Battery → Battery usage and look at the per-app breakdown over 24 hours. Compare across a few days with different interval settings. That number is the only one that matters on your device, with your photos, at your usage pattern — benchmark figures from someone else's phone will not transfer.
When an overlay genuinely does cost you
Overlays that animate continuously, load images over a network each time, or run a foreground service with a persistent notification are a different proposition. If an ambient photo app requires an account and a cloud library, the battery cost is not the overlay — it is the syncing behind it.
Bubbles In Time draws from your own gallery — family, friends, pets, places — and shows them as translucent bubbles over any app, then lets them go.
Quick answers
Does a floating photo overlay drain my battery? Not measurably, if it renders a local image occasionally and does nothing between appearances. Sustained drain comes from wake locks, network polling and continuous animation.
Does Doze stop it working? Doze defers background work when the phone is idle. An ambient photo app that shows photos while you are using the phone is not competing with Doze, because the phone is not idle.
Will a shorter interval hurt battery? Slightly, and less than you think. The screen is the expensive component and it is already on when you see a photo.
Related: The complete guide to floating overlays · Do overlays drain your battery? · Overlay vs notification vs widget