Flatpak image contains screenshots about flathub

[bbhtt]

Can you explain what you mean?

Screenshots from the metainfo file are mirrored by flatpak-builder when building the Flatpak and saved into share/app-info/media directory by appstreamcli. This is done to have a local cache of the images and to preserve privacy so that you don't need to connect to random webservers to download images.

I don't see any issue in this? Most screenshots are only a few kilobytes.

[mrbid]

They are pretty big (2.2M) Why is it good? When I want to download an app I have internet, the screenshots are taken from the Internet. When I have the app, I don't care about screenshots.

Can you give us more information about the app in question? 2.2 MB is not crazy big but it does sound like a lot for just a few screenshots.

I would like to see if maybe they have a lot of screenshots or if there is only a few but the compression is bad?

If it's the compression being bad maybe that is an issue that could be addressed.

If there are too many screenshots, maybe a limit could be introduced or if a limit on the number of screenshots already exists it could be reduced possibly?

Either way please provide more information and examples about the apps you are referring to please! ty

[soyersoyer]

This is done to have a local cache of the images and to preserve privacy so that you don't need to connect to random webservers to download images.

Does it download all of the screenshots from all of the applications? Or when and how does it preserve the privacy?

A few months ago my application (hu.irl.cameractrls) on flathub was 600 kB, and I think that's a good size for such an application. Now it's 2.7 MB. The app doesn't use the screenshots. And I can see the screenshots in the software app even if the app is not installed.

[bbhtt]

Does it download all of the screenshots from all of the applications?

When the build is done on Flathub servers, appstreamcli downloads the images, converts it to thumbnail and original variants and saves it. This is shipped in every Flatpak.

Or when and how does it preserve the privacy?

a) Screenshots are mirrored to Flathub's CDN, so whenever you open an app in GNOME Software/Discover, it doesn't connect to a random website which may or may not be evil

b) It is also saved to the local cache for exactly the same reason.

And I can see the screenshots in the software app even if the app is not installed.

Those are fetched from Flathub directly when not installed.

The app doesn't use the screenshots.

What do you mean? I see a bunch of screenshots here https://flathub.org/apps/hu.irl.cameractrls

A few months ago my application (hu.irl.cameractrls) on flathub was 600 kB, and I think that's a good size for such an application. Now it's 2.7 MB

So are you saying the size increased due to screenshots? Download and install size can increases for a number of reasons.

[mrbid]

The app doesn't use the screenshots.

What do you mean? I see a bunch of screenshots here https://flathub.org/apps/hu.irl.cameractrls

He means that his app doesn't use them aka require them to operate, so there's no need for them to be packaged with his app download in his opinion - as he theorizes it might be the reason his 600 KB app jumped to 2.7 MB

So the question now is when did FlatHub start packaging images into the downloads for apps? This way the user can correlate if this is the reason.

Also @soyersoyer did you check the size of the screenshots in the downloaded app? do the size of them match up with the increased download size of your app? 600 KB to 2.7MB (+2.1 MB) ?

https://flathub.org/apps/hu.irl.cameractrls

Hm only 6 images, are you sure they are 2.1 MB total? I thought flathub was compressing user images before caching them on the CDN etc, maybe not.

All your images only add up to 730 KB.

So that doesn't fully explain a 2.1 MB increase in your downloaded app.

[bbhtt]

Each image is converted into 4 thumnails:

tree ~/.local/share/flatpak/app/hu.irl.cameractrls/current/active/files/share/app-info/media/hu/irl/cameractrls/f1e3c4bb469678af77c738d1d15f6786/screenshots

├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── image-1_orig.png
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── image-2_orig.png
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── image-3_orig.png
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── image-4_orig.png
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── image-5_orig.png
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
└── image-6_orig.png

1 directory, 30 files

[bbhtt]

This is not an issue, it is just how things work with appstream.

[mrbid]

Each image is converted into 4 thumnails:

tree ~/.local/share/flatpak/app/hu.irl.cameractrls/current/active/files/share/app-info/media/hu/irl/cameractrls/f1e3c4bb469678af77c738d1d15f6786/screenshots

├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── image-1_orig.png
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── image-2_orig.png
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── image-3_orig.png
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── image-4_orig.png
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── image-5_orig.png
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
└── image-6_orig.png

1 directory, 30 files

I figured that might have been the case

[soyersoyer]

But did appstream work differently last year?

[bbhtt]

But did appstream work differently last year?

Yes we switched from deprecated appstream-glib to libappstream https://docs.flathub.org/blog/improved-build-validation

[soyersoyer]

I reduced the number of screenshots to 1, so its under 1MB again! :)

[razzeee]

If you think this should work differently, raise it here https://github.com/ximion/appstream/issues

[soyersoyer]

I am a bit tired, maybe next week.
It's a lot of excess data. 5 000 000 download / day * 1 MB unnecessary data / download = 5 TB unnecessary data / day ~ 150TB /month, and this is not only network traffic but also storage space on the user side.