Had no free disk space on my iPhone 5... but now I do? I realized yesterday that I had no disk space left on my iPhone 5 after I got spammed with iOS notifications that my apps could not be updated (due to lack of disk space). This morning I woke up to about 350 MB of free space - and I didn't do anything.

I don't know what the exact numbers were for usage (Settings --> General --> Storage &amp; iCloud Usage --> Manage Storage), so I don't know what happened. As well as gaining free space, about 10 apps were updated.

My best guess is that there is some internal routine to compress images, since at full resolution they take up a fair amount of space, but even minimal lossy compression can save megabytes per photo without a noticeable loss in quality.

Is there such a documented process, or did something else happen? In any case, I wish I would have screenshotted the storage usage before this happened...
You can try to do the most obvious and smart things that free up space on your iPhone. Which are


Upgrade to iOS 10.3: Apple’s new file system, Apple File System (APFS) included in iOS 10.3 is optimized for flash and solid-state drive storage. According to [Apple Insider][1], there has been a gain of space of almost 8GB in a 256GB model. But don’t expect a gain of 6-8GB in your 16GB or 32GB. As Apple Insider explains, the more memory you have, the more free space iOS 10.3 will reclaim.
Backup Photos using Google Photos: Google Photos is basically a cloud storage for your photos. It works great with iOS too. Google Photos offers unlimited photos and videos for free, up to 16 megapixels and 1080p HD. Photos that are safely backed up can be removed from your device’s storage in just a tap.
Remove “Other” Data on your phone: When you connect your iPhone to a computer and open iTunes, you would encounter the “Other” section in little iTunes usage bar graph. Check out this tip by OSXdaily on how to manage this issue. http://osxdaily.com/2013/07/24/remove-other-data-storage-iphone-ipad/
Use Progressive Web Apps (PWA): Although PWA offers to free up app space, iOS doesn’t fully support it at this point. Some features
such as Add to Home Screen and Push Notifications, are available in
some form in Safari but are not implemented in standard ways. To
give you a comparison of the Space utilization for an App VS PWA,
the Twitter app has a size of 196 MB in the app store. But the PWA
app for twitter is just 1-2MB!
Stream your music instead of downloading them
Remove offline reading list data in Safari: This can be done by navigating to Settings and then General > Usage > Manage Storage > Safari. Then, go to Offline Reading List and tap Delete.
Clear the Safari browser cache: To clean up the cache, simply go to Settings > Safari > Clear History and Website Data.
Remove items from iBooks
Disable using My Photo Stream: Go to Settings > iCloud > Photos, then turn off My Photo Stream
Delete Burst Mode photos
Don’t keep both photos when you enable HDR mode. Go to Settings > Photos &amp; Camera, then deselect Keep Normal Photo


If you have tried most of the above-mentioned tips and still find yourself with less storage space then follow this trick to gain more space.  This trick forces iOS to clear it OS cache. There has been an ongoing argument that since this is a system level cache it would have been freed anyway when you actually needed the space. But this does not seem to work if you are in the middle of taking a video and run our of space.
http://techathlon.com/free-gbs-space-iphone-deleting-photos-apps-files/.