I haven’t tested this, but the " Local assets" documentation implies that they are already embedded in the app. But of course if you publish new images in an OTA update then they will be served from a CDN, but will be downloaded before launching the update.
You might want to look into the new Expo Image library, though. Expo SDK 48 Beta has just been released and includes a release candidate of Expo Image:
My problem is that I have about 1000 assets. Manually prefetching them would be impossible. Is there a possibility to prefetch a directory?
And what you said about the local assets is partially true. The assets are stored locally (in the APK) in Android, but not in iOS. When built with EAS (even as a standalone bundle) it gets uploaded to the expo server.
The Expo Image Library would only partially solve my problem, but I am still looking for a way to include all assets into the bundle, thank you for your input tho!