Depends on a client, if you are using Damus then it defaults to nostr.build
I can’t speak for any other clients, but you can store your media anywhere you want and share URLs 🐶🐾🫡
nostr:npub137c5pd8gmhhe0njtsgwjgunc5xjr2vmzvglkgqs5sjeh972gqqxqjak37w managing among other contributors, Nostr.Build, maybe he can give u an answer 💜
Discussion
Yep. This is a good answer. Each client may have a different way to store media. I guess technically you could also "embed" your image in a note but that would make the note VERY heavy so it won't load properly on clients (and also it won't be supported by most of them). But it's technically still a possibility.