cross-posted from: https://lemmy.world/post/12315554
Post is displaying URL image in Thunder but not Voyager
Hi,
I’m comparing Lemmy Android app clients and I’m between Thunder and Voyager.
I noticed something weird with Voyager. There was this post it displays an image in the timeline using Thunder but it doesn’t in Voyager.
Is it some configuration that I need to tweak in Voyager?
Also, is there some config to display short text about the post if has image? Like some description below if available
Thanks
You might have the “scrape missing link previews” setting enabled in Thunder. It’s in general settings.
Instances will provide a preview thumbnail for links, but will sometimes fail to find one for a given link.
Thunder is able to have a second go at finding an image to display with a link, when the instance doesn’t provide one with a given link.
There is a setting for displaying a text preview of the post body, in settings>appearance>posts.
You can also just search the settings to find these.
How does it works? Technically is it connecting directly to the website and retrieving a thumbnail?
Edit: BTW, mine is off. Do you also see the image when you open the link using your Thunder Android app ?
Yes, it goes and grabs a thumbnail directly from the website being linked.
I do not get an image, I keep the setting off. Really odd that you do, then.
Am I the only one with this feature off and seeing the image?
I do not know.
Hi there, thanks for the question! I think MentalEdge pretty much answered the question, but I’d like to give some clarifications!
By default, Thunder will only grab thumbnails that come back from the instance. If the instance doesn’t provide a thumbnail, then Thunder will just show the URL link. This is what I’m experiencing as well with the link that you provided.
There is an additional option in the settings which allows Thunder to attempt to get thumbnails when none are provided. This is “Scrape Missing Link Previews”. This option is off by default, so you’ll have to manually enable it to turn it on. In order to get the thumbnail, Thunder has to retrieve the metadata information of the link (which means that it’ll have to “connect” to the site to do so)
I believe this option came from a time where Lemmy had an issue with thumbnail previews not being populated which meant that most posts were not showing up properly.
As for why you’re seeing the thumbnail even when the option is turned off, I’m not too sure. If you’d like, you can submit a new issue on our GitHub page with some more details and I can take a look into this for you!
Ok, I’ll submit an issue on GitHub. What should I share other than the screenshot of the app showing the image of the link and the setting for Scrap Missing Link off?
Also, do you mind commenting about privacy and security concern about this feature on?
What should I share other than the screenshot of the app showing the image of the link and the setting for Scrap Missing Link off?
I would try to share as much detail as possible for us to be able to reproduce the issue. If we can’t reproduce it, then it’s very unlikely that we’ll be able to find the cause of it (and therefore fix it). The best way to do this is to start from a clean install of Thunder and perform the minimal steps to get the issue to show up.
Aside from steps to reproduce, I would also suggest putting the version of Thunder you’re using, and any other relevant information! (Android/iOS version)
Also, do you mind commenting about privacy and security concern about this feature on?
Of course! I’ll try to give the best summary based on what I remember, and all the source code is available on GitHub if you’re interested to take a look.
If you have the setting turned on, Thunder will attempt to fetch missing thumbnails for posts that don’t already have one (in particular, posts that contain an external link). If the instance already contains a thumbnail, then it will prioritize that one and won’t try to find thumbnails even with the setting turned on.
If there is no thumbnail (which is generally pretty rare now), then Thunder will make a request to the external URL (linked from the post) and attempt to fetch any metadata information from it. This metadata sometimes contains a link to a thumbnail which Thunder proceeds to use.
This process would be no different than if you were to tap on the link yourself to view the site. This does mean that Thunder will connect to the site in order to retrieve the metadata from it. The only difference here is that Thunder changes the “user agent” when performing the request to fetch information from the site to a more generic one. The user agent often contains information about the application and version being used to contact the external URL, so this alleviates some (but definitely not all) privacy concerns associated with this.
This is the extent of what I can remember, and as always, feel free to suggest any feedback that you see fit (whether it be privacy/security concerns or otherwise)! I’d be happy to take a look at them and see if it’s feasible to do. Thunder is still mainly maintained by a only a few people, and we all do it on a voluntary basis so there’s definitely always room for improvement.
I hope this answers your questions!
Yeah, but what’s the question? Thunder does additional stuff to Voyager?
How it does it? If there is no image in the instance, the scrap link option is off in my app, how does it retrieve the thumbnail? Is it some security or privacy concern?
