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Is there something about Mastodon and the Fediverse that you need help with?
Reply to me or send me a DM and I'll try to help if I can, or put you in touch with someone else who can help.
Don't worry if a question seems silly or obvious! The idea of this account is to especially help new people.
@feditips @feditips
Q: Say I'm using the Mastodon app, looking at photos posted by other people on different instances. And maybe one looks great...so I decide to see what other photos that person has posted.
But in the app, I can only see remote photos back 2-4 weeks (unless someone on my own instance has boosted the photo). I get it. My instance can't keep a copy of every photo in the fediverse - there has to be a limit.
I've learned that if I want to see someone's portfolio, I need to use my browser and essentially do my viewing as a guest on the remote instance, with limited functionality to like or comment while not logged in.
My question is: why can't the Mastodon app make an external lookup itself and show me an old photo from inside the app, without me having to switch to a browser? Is that a difficult thing for an app to do - to fetch old photos for a quick look-see on my phone or tablet, on demand, without burdening my instance with storing that photo?
Does that question make sense?
It's a really good question!
If one person on your server has followed the account, all the posts after that moment should be visible from your server. However, anything before that may not be.
The solution to this would be "backfilling", where your server automatically checks for older posts when someone follows an account (or perhaps just interacts with it?).
Backfilling can be very resource intensive, which is apparently why it hasn't been implemented yet, but...
(1/2)
...according to the official Mastodon roadmap (at https://joinmastodon.org/roadmap) one of the features being planned is "Explicit controls to fetch more data from origin server".
Presumably this would be a button you could press on a profile to fill in more of the older posts, without you having to leave your server or go to the other server's website.
By the way, backfilling already happens with pinned posts, which is why it's a good idea to pin an intro post on your profile.
(2/2)
@feditips Ah, thank you! I look forward to having a backfilling option. As a photographer who uses Mastodon to find other photographers, the limited backview has been (mildly) disappointing. But the browser is an okay workaround.
It makes sense that backfilling could, sadly, be a resource hog on a server.
Re: "If one person on your server has followed the account, all the posts after that moment should be visible from your server. However, anything before that may not be."
This doesn't seem to be in effect here yet. If I look at, say, @kylev, for example, any media he has posted older than 24 days only shows as a blurred gradient in the app. But I and others on my server have followed Kyle for a long time. It seems boosting keeps media alive on my server, but simple following does not.
Again, thank you for the quick answer!
Bob
"any media he has posted older than 24 days only shows as a blurred gradient in the app."
Ahhh... okay... possibly a different issue them? It sounds like the post is there, but the media file is not displayed.
That might be more to do with your server's media storage provider not displaying it properly, or perhaps your server has some resource-saving settings that affect this.
AFAIK there's nothing in Mastodon to stop a post's photo being visible.
For what it's worth, on my tiny one person server I can see all old photos and never see blurry ones, but I don't have to worry about providing resources to cope with lots of other members.
I'm sure they will welcome donations to help 
@BobHorowitz I've noticed the same thing, and have been meaning to write to seb and Moritz to ask about it. Now I'll just defer to you! I've just assumed they reduced the image storage time to keep thing manageable, but it would be nice to know for sure.