# Do i.stack.imgur.com PNGs and GIFs ever expire?

The GIF at https://i.stack.imgur.com/cdkOW.gif is linked here and here but now doesn't work. If I look at the same file name like this https://i.imgur.com/cdkOW.gif I see a different image.

Five upper/lower case alphanumerics give $(26+26+10)^5$ = 916,132,832 combinations. Are they being recycled? Are any or all imgur PNGs or GIFs in stackexchange going to expire? If so, how soon? I remember when I first learned that FedEx tracking numbers were being recycled constantly; I was shocked until I did the math, then shocked again when I realized a few more digits would have fixed that, then un-shocked when I realized that expiration was probably OK after weighing the tradeoffs. With only five character file names, these imgur files look like someone has already planned on eventual expiry.

update: The breakage of the link seems to have been temporary, i.e. it works now. But I'm still curious, are the imgur links we use in stackexchange supposed to be permanent?

• It is highly likely the 5 characters can host significantly less than a billion images - there are likely to be check bits and other features. Should the limit be reached, nothing prevents the system switching to p.stack.imgur.com for new images; however simply adding extra characters to the hash would be a better, though slightly non-trivial change. Ultimately though this question belongs on the main meta. – JCRM Jan 26 at 9:43
• I think that it's a bit impractical to move a 2.5 year old question with two answers to a different meta. These days I ask both there and here, depending on scope. – uhoh Jan 26 at 12:00

According to Jeff Atwood, Stack Exchange entered a 1 year agreement with imgur for dedicated image hosting:

We engaged in a 1 year agreement to formally support imgur, which also involved us getting

• a dedicated server on premises with them
• a custom domain name

While I cannot speak to the specifics of the Stack Exchange/Imgur agreement, the base Imgur site never deletes images unless deletion is requested.

They originally had deleted inactive images after 6 months, and offered pro accounts a "never-expire" feature. In February 2015, Imgur made that a baseline feature.

We’re phasing out Pro subscriptions…and making the Pro features completely free for every Imgur user!

It is likely that as because Stack Exchange has a dedicated on premises server their image expiration details are determined by Stack Exchange itself, and are likely set to never expire currently.

• This is probably as good of an answer as is possible. I'm still worried about the individual five-character names for the images. Knowing the sever will be there for a while is great, but will the individual images stick around as well? (I'd guess probably; 916,132,832 is pretty big for SE-specific images). – uhoh Jul 7 '17 at 15:12
• I've added a caveat answer – uhoh Jan 24 at 23:56