If iMessage won't send photos because storage is full, free a few hundred MB of device space first: empty Photos > Albums > Recently Deleted and delete one or two large videos. Then trim Messages itself in Settings > General > iPhone Storage > Messages > Review Large Attachments, where years of saved photos and videos often hide. Once the phone has breathing room, sending works again.
TL;DR
- A near-full phone can block iMessage from preparing and sending photos.
- Messages stores every received attachment; it's often a hidden multi-GB pile.
- Trim it at Settings > General > iPhone Storage > Messages > Review Large Attachments.
- Free a few hundred MB of device space and sending usually recovers.
- Deleted photos stay in Recently Deleted ~30 days, so back up first.
Why can't I send photos in iMessage when storage is full?
Before sending, iMessage has to compress and stage a temporary copy of the photo. On a phone with only a few hundred MB free, there isn't room to do that, so the message hangs, shows a red "Not Delivered," or the attach button does nothing. It's the same root cause as a camera that won't shoot: the system needs working headroom it doesn't have.
The fix is to push free space back up, and Messages itself is often where the wasted space is hiding.
How do I see what Messages is using?
Open Settings > General > iPhone Storage and tap Messages. iOS breaks it down into Photos, Videos, GIFs/Stickers, and Other. Tap Review Large Attachments to see the biggest items, then swipe to delete the ones you don't need. Group chats with lots of media are usually the worst offenders, and this category routinely holds several gigabytes that people never realize is there.
You can also set messages to auto-expire: Settings > Messages > Keep Messages > 30 Days or 1 Year instead of Forever. iOS will warn you before deleting older conversations.
What's the fastest way to free device space right now?
Do these in order and try sending after each:
- Empty Recently Deleted. Photos > Albums > Recently Deleted > Select > Delete All to release space iOS is still holding.
- Delete one or two big videos. A single 4K clip can be 300 MB to 2 GB, often enough on its own.
- Trim Messages attachments. Use Review Large Attachments as above.
- Offload an unused app. Settings > General > iPhone Storage > Offload Unused Apps keeps data while freeing the binary.
Reopen the conversation and resend. If a message still shows "Not Delivered," tap the red exclamation and choose Try Again.
Where does iOS stop helping?
iOS shows the Messages breakdown and a sorted storage list, which is helpful for finding obvious bulk. But it won't flag the duplicate photos, near-identical bursts, and forgotten screen recordings scattered across your library that quietly keep the phone full. It treats all of that as worth keeping, so you can trim Messages and still be stuck if your real overflow is redundant media elsewhere.
If your storage looks full with nothing obvious to remove, see iphone storage full but nothing to delete what's actually using it.
What if sending still fails after freeing space?
- Empty Recently Deleted again. Deleted media only frees space once that album is cleared.
- Restart the phone so iOS recalculates free space.
- Confirm it's storage, not signal. A failure tied to Wi-Fi/cellular or iMessage being down is a different problem; check that iMessage is on in Settings > Messages.
For a calm, ordered cleanup that frees real gigabytes, follow how to free up 10GB on iPhone in 10 minutes safe order.
Will trimming Messages or deleting photos lose anything important?
Deleting a Messages attachment removes that photo or video from the conversation, so save anything you want to keep to Photos first (tap the attachment, then the share/save icon). Photos you delete from your library move to Photos > Albums > Recently Deleted and stay recoverable for about 30 days. If you use iCloud Photos, make sure originals have synced before mass-deleting, and back up to iCloud or a computer first if you're unsure.
FAQ
How much free space do I need to send a photo in iMessage?
Usually a few hundred MB. iMessage needs room to compress and stage the image, so freeing 300-500 MB is typically enough for sending to start working again.
Why does Messages use so much storage?
Messages saves every photo, video, GIF, and sticker you send and receive by default, with no expiry unless you set one. Active group chats can pile up several gigabytes. Check it in Settings > General > iPhone Storage > Messages > Review Large Attachments.
Does setting Messages to auto-delete after 30 days help?
Yes. Settings > Messages > Keep Messages > 30 Days automatically clears old conversations and their attachments, which can free significant space over time. iOS warns you before removing anything older.
If Messages and your photo library keep filling the phone, the lasting fix is clearing the duplicates and big videos iOS ignores. Cleanor for iPhone finds and removes them in a few taps so you can fix a full phone fast and keep sending. For the full method, see how to free up iPhone space.