How to Batch Convert Your iPhone Library to AVIF

Converting one photo to AVIF takes a few seconds. Converting 10,000 photos is a different kind of job. This guide walks through the workflow for batch-converting a full iPhone library, the order to do it in, and what to expect along the way.

Why Batch Convert?

A typical iPhone library that's been collecting photos for a few years sits at 30-80 GB. Of that:

• Photos from the iPhone Camera (HEIC) are decently efficient already.
• Old JPGs (imports, downloads, AirDrops from older devices) are 2-3x bigger than they need to be.
• Screenshots (PNG) are often 5-10x bigger than they need to be.

Converting the whole library to AVIF reclaims 30-50% on average. For a 60 GB library, that's roughly 20-30 GB back without deleting a single memory.

Before You Start: Three Quick Decisions

1. Pick a Quality Target

For 99% of users, the default quality is the right choice. It produces files about 30-40% smaller than HEIC and 60-70% smaller than JPG, with no visible quality difference on iPhone.

If you're an archivist, pick the highest quality. The files are still smaller than HEIC, just by a more conservative margin.

If you want maximum savings on photos you'll mostly just store, drop the quality. You'll start to see softening on close inspection but for the casual viewer it's invisible.

2. Decide What to Keep Original

Two common strategies:

• Recent photos stay HEIC. Anything from the last 30-60 days is more likely to be shared or edited, so the instant-save behavior of HEIC matters. Convert older photos to AVIF.
• Everything converts. Simpler. Recent photos still work fine in AVIF for almost all use cases.

3. Decide on a Safety Net

Photos' built-in Recently Deleted album holds your originals for 30 days after conversion. If you want a permanent safety net, stash originals in HEVCut's Personal Vault before converting. The Vault keeps full-quality originals encrypted and private; you can restore any of them anytime.

The Workflow

Step 1: Plug In and Find Wi-Fi

Big batch conversions work best when:

• The phone is plugged into power (the work is real work for the device).
• The phone is on Wi-Fi (iCloud needs to sync the smaller copies back up afterward).
• The phone is not too hot (a cool phone stays at full speed).

Ideal time: overnight, on your nightstand charger.

Step 2: Open HEVCut and Set Up AVIF

1. Open HEVCut and tap the Photos tab.
2. Tap the gear icon to open Compression Settings.
3. Set Output Format to AVIF.
4. Confirm the quality level. The default is fine.

Step 3: Pick a Slice

For your first batch, don't try the whole library at once. Pick a tighter slice so you can see results quickly:

• By year: start with the oldest year. Convert it, check a few photos, confirm you're happy.
• By format: filter to JPG first. JPGs deliver the biggest wins (60-70%).
• By size: filter to larger than 5 MB. These are the storage hogs.

Step 4: Send to the Queue and Walk Away

Select the photos, tap Compress, and lock your phone. The queue runs in the background. You can use your phone normally; HEVCut pauses when the screen is unlocked for active use and resumes when you're idle.

On a typical overnight session, expect 1,000-3,000 photos converted, depending on photo size and your iPhone model.

Step 5: Verify, Then Move On to the Next Slice

After a batch finishes:

• Open Photos and scroll through the album you converted. Spot-check a few photos.
• Confirm Memories and search still work as expected (they will).
• Move on to the next slice (next year, next format, next size band).

Step 6: Recover the Space

After conversion, the original files move to Recently Deleted for 30 days. The space they used isn't truly free until they're permanently removed. Two options:

• Wait 30 days. Photos clears them automatically.
• Empty Recently Deleted now. Photos → Albums → Recently Deleted → Select → Delete All. The space is reclaimed immediately.

If you stashed originals in the Personal Vault, you can empty Recently Deleted right away with no risk.

Common Concerns

Will my phone slow down during conversion?

HEVCut is designed to be a polite background worker. You can use your phone for browsing, messaging, watching video — the queue gives way to whatever you're doing. Big batches run fastest when your phone is idle.

What if my phone runs out of battery mid-batch?

The queue resumes from where it left off when you plug back in. Nothing is lost.

What if I have a really big library, like 50,000+ photos?

Plan on a few overnight sessions, not one. Pick a different slice each night until the library is converted. The work is incremental and you can see savings build night-over-night.

Does iCloud need to re-upload the converted photos?

Yes, but the converted files are smaller than the originals, so the upload bandwidth is less than what was originally used. Overnight on Wi-Fi handles this without thinking about it.

What about RAW and ProRAW photos?

HEVCut can convert ProRAW captures to AVIF. The savings are dramatic (often 70%+) because ProRAW files are huge. Keep originals in the Vault if you might re-edit them.

Can I convert just my Screenshots album?

Yes. Open the Screenshots album in HEVCut and convert from there. Screenshots are usually PNG, which compresses to AVIF spectacularly well (often 70-85% smaller).

After You're Done

Once the library is converted:

• Photos works the same. Memories, search, Faces, Places, Albums — all unchanged.
• iCloud is smaller. Your iCloud bill may drop a tier next month.
• Sharing works. AVIF plays on modern iPhones, Macs, Android, Windows 11, and every major browser. For very old recipients, export to JPG.

Bottom Line

Converting an entire iPhone library to AVIF sounds intimidating but is mostly a matter of plugging in and queueing up. With HEVCut, the work happens on-device, in the background, while you sleep. The reward is 30-50% smaller library with no quality loss and no deletes. For most users, this is the single biggest one-time storage win possible without giving up any photos.