i.4cdn.org serves all user submitted content and thumbnails (a downsampled preview of the original media) for 4chan.org and 4channel.org.
s.4cdn.org serves static/site images for 4chan.org and 4channel.org.
User images: https://i.4cdn.org/[board]/[4chan image ID].[file extension]
Thumbnails: https://i.4cdn.org/[board]/[4chan image ID]s.jpg
The s after the image ID indicates the file is a thumbnail.
Country flags:
Sprite sheet: https://s.4cdn.org/css/flags.css
Individual images: https://s.4cdn.org/image/country/[country code].gif
Board flags:
Sprite sheet: https://s.4cdn.org/image/flags/[board]/flags.css
Individual images: https://s.4cdn.org/image/flags/[board]/[code].gif
Spoiler image: https://s.4cdn.org/image/spoiler.png
Custom spoilers: https://s.4cdn.org/image/spoiler-[board][1-5].png
Note about custom spoilers:
Different boards can have different numbers of potential custom spoilers. For boards with custom spoilers enabled, a custom spoiler thumbnail is randomly assigned to each spoilered image on a page every time a new post is made and the page is refreshed.
| Icon | Description | Location |
|---|---|---|
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Thread closed or archived | https://s.4cdn.org/image/closed.gif |
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Thread will remain at top of board | https://s.4cdn.org/image/sticky.gif |
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Admin capcode verification | https://s.4cdn.org/image/adminicon.gif |
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Moderator capcode verification | https://s.4cdn.org/image/modicon.gif |
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Developer capcode verification | https://s.4cdn.org/image/developericon.gif |
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Manager capcode verification | https://s.4cdn.org/image/managericon.gif |
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Founder capcode verification | https://s.4cdn.org/image/foundericon.gif |
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Replaces OP images that have been deleted | https://s.4cdn.org/image/filedeleted.gif |
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Replaces reply images that have been deleted | https://s.4cdn.org/image/filedeleted-res.gif |