The basics
What a media server is
Relays only carry text. A photo or video is too big for that, so it goes to a media server instead, and your note holds a link to it. Nostr media servers speak a shared language called Blossom, so any Nostr app can read from them.
A photo on a Blossom server is named by its fingerprint (a hash of the file). The same photo has the same name on every server, so it can be copied between servers and still be checked.
Your account publishes a list of your media servers. Other apps read that list to find your files.
When you post
Where a photo goes when you post
- The app first saves the photo on this device, in your vault.
- It then uploads it to all of your outside media servers at once.
- As soon as one of them has it, the note is sent. The other servers keep uploading in the background.
If no outside server takes the photo, the post is not lost. It waits under Settings → Media Servers in Waiting to send, and sends itself when a server answers. Tap Try sending now to retry straight away.
Posting a photo still needs a public media server. A photo that is only on your phone can't be seen by anyone else, so the app won't post it without an outside server.
Your list
Add or remove a media server
Open Settings → Media Servers. It sits in the Relays group, under Relays.
- Add: type the server's address (for example
blossom.example.com) in the box and tap the add button next to it. If you leave outhttps://, the app adds it. - Remove: tap the red button next to a server (a minus sign on iPhone and Mac, a bin on Android).
Each change is saved and your updated list is published to your relays.
If you set up Sync with Vault on Mac, your Mac is used as a media server too. It shows at the top of the page and you don't need to add it by hand.
In the web app, the same page is Settings → Media Servers. Use Add and Remove, then Save and publish. Test checks that a saved server answers. The web app uploads to the server marked first first. If you have never published a list, it starts from two default servers. It also needs at least one server in the list.
There is no button to reorder servers. In the web app, a server you add goes to the end of the list.
Copies you own
Mirroring
Mirroring brings your own photos back from your media servers into your vault on this device, so they work offline and you keep a copy if a server goes away. Both controls are on the Media Servers page:
- Mirror Now downloads your media from your outside servers to this device, once. It shows progress while it runs.
- Auto-Mirror Media keeps doing it for you.
Other people's photos
Media & Cache
When you look at photos and videos in the feed, the app keeps temporary copies so they load faster next time. You control this in Settings → Media & Cache, in the Feed & Display group. The web app doesn't have this page.
- Autoplay Videos plays videos as you scroll.
- Prefetch Profile Pictures loads profile pictures ahead of time for smoother scrolling.
- Disable Media Cache stops saving copies, so media downloads again each time.
- Keep Media For sets how long copies are kept: 1, 3, 7, 14 or 30 days, or Never.
- Clear Media Cache deletes the temporary copies to free space. Your vault and your media servers are not touched.
On Android there is one more switch, Use Local Blossom Cache. It loads media through a Blossom cache app on the same phone, when one is running. Uploads never go through it.
Your own device
Your device as a photo server
Your phone or Mac can also serve your photos to others over the mesh. That is covered on The mesh. It adds to your media servers and doesn't replace them, so you still need a public one to post.
The web app can already load photos over the mesh. The Load photos over FIPS mesh switch on its Media Servers page turns that off. It is on by default.