The iPhone camera settings that save the most storage
Short answer
Record video at 1080p and 30 fps instead of 4K (Settings › Camera › Record Video), keep Settings › Camera › Formats on High Efficiency, and turn on Optimize iPhone Storage if you use iCloud Photos. Video resolution matters far more than anything else.
1. Video resolution and frame rate
Go to Settings › Camera › Record Video. Each option lists roughly how much space a minute takes on your iPhone, and 4K at 60 fps is several times the size of 1080p at 30 fps. Unless you'll edit or watch on a big TV, 1080p at 30 fps looks the same on your phone.
Slow motion has its own setting under Record Slo-mo. 1080p at 240 fps is much bigger than 120 fps.
2. Photo and video format
Settings › Camera › Formats › High Efficiency saves photos as HEIF and video as HEVC. Apple says these compress better than JPEG and H.264 at the same visual quality. Most Compatible uses the older, larger formats. Keep High Efficiency on unless something you use can't open it.
3. Live Photos
A Live Photo records 1.5 seconds before and after the shot, so each one stores a short video alongside the still. To keep them off: tap the Live Photo button in Camera so it shows a slash, then turn on Settings › Camera › Preserve Settings › Live Photo so it stays off.
4. iCloud Photos
If you pay for iCloud storage, go to Settings › [your name] › iCloud › Photos and choose Optimize iPhone Storage. Full-size originals stay in iCloud and your iPhone keeps smaller versions. In iOS 27 the option sits one level deeper, under iPhone Storage.
5. Messages
Settings › Apps › Messages › Keep Messages set to 1 Year stops years of photos and videos piling up in old chats. It permanently deletes older conversations and their attachments, so save anything you want first.
How SlashPhotos helps
SlashPhotos looks at how you actually shoot. If your recent videos are 4K at 60 fps, it tells you, with the exact Settings path to change it. A monthly report shows how much your library grew and how much you cleared. These tips are free.
Questions
Is 4K or 1080p better on iPhone?
4K keeps more detail for big screens and editing. 1080p takes a fraction of the space and looks the same on a phone. For everyday clips, 1080p at 30 fps is a sensible default.
Does HEIC save space compared to JPEG?
Yes. Apple's High Efficiency format compresses better than JPEG at the same visual quality. Keep it on unless you need JPEGs for another device.