Postauto
Start free

Image and video checker

Choose a photo or a clip. It is measured here in the page, against every one of the 23 formats Postauto publishes to, and each one that would refuse it says why and what to do instead. The file is never uploaded.

No file yet. Every format below shows where its rules came from.

Nothing is uploaded. The size comes from the file itself, the type is read from its first bytes rather than from its name, the pixels come from decoding it here in the page, and a clip's length is read by asking a detached video element for its metadata. There is no request to make: this page has no server side.

Every format

23 of them rather than 21, because a format is a network and a shape of post. Instagram's feed, its Reels and its Stories are three different contracts, and a file the first refuses the third will take.

Nothing is recorded for 6 of them. Reddit, dev.to, Hashnode, Ghost, Lemmy and Nostr have no file rules in Postauto at all. Their rows say so rather than showing a tick, because "nothing we know objects" and "this file is fine" are different answers and only one of them is true.

An ordinary phone photo

Portrait, straight off a recent handset, nothing done to it. The single most common thing anybody attaches.

3,024 x 4,032, 3,600,000 bytes, image/jpeg

4 of the 20 formats that can carry it would refuse it. 6 of those have nothing recorded either way.

  • Bluesky Post Bluesky takes a photo up to 2 MB and this one is 3.6 MB. Save it at a smaller size, or leave it off the Bluesky copy of this post.
  • Mastodon Post Mastodon takes a photo up to 8,294,400 pixels in total and this one is 3024 by 4032, which is 12,192,768. Scale it down before publishing.
  • Instagram Post Instagram takes a photo no taller than 0.80:1 (width to height) and this one is 0.75:1. Crop it wider, or send it to a format that takes a tall picture.
  • Threads Post Threads takes a photo up to 1440 pixels wide and this one is 3024. Scale it down before publishing.

A minute of phone video

Landscape, the clip you would take of a demo or a talk. Its exact shape and length are below it.

1,920 x 1,080, 62 seconds, 120,000,000 bytes, video/mp4

11 of the 22 formats that can carry it would refuse it. 5 of those have nothing recorded either way.

  • X Post X publishes photos only, so this video would not go out with the post. Send it to a channel that takes a video, or leave it off the X copy of this post.
  • LinkedIn Post LinkedIn publishes photos only, so this video would not go out with the post. Send it to a channel that takes a video, or leave it off the LinkedIn copy of this post.
  • Bluesky Post Bluesky publishes photos only, so this video would not go out with the post. Send it to a channel that takes a video, or leave it off the Bluesky copy of this post.
  • Mastodon Post Mastodon takes a video up to 104 MB and this one is 120 MB. Save it at a smaller size, or leave it off the Mastodon copy of this post.
  • Telegram Post Telegram takes a video up to 50 MB and this one is 120 MB. Save it at a smaller size, or leave it off the Telegram copy of this post.
  • Discord Post Discord takes a video up to 10 MB and this one is 120 MB. Save it at a smaller size, or leave it off the Discord copy of this post.
  • Instagram Story Instagram takes a video up to 100 MB and this one is 120 MB. Save it at a smaller size, or leave it off the Instagram copy of this post.
  • Facebook Post Facebook publishes photos only, so this video would not go out with the post. Send it to a channel that takes a video, or leave it off the Facebook copy of this post.
  • Threads Post Threads publishes photos only, so this video would not go out with the post. Send it to a channel that takes a video, or leave it off the Threads copy of this post.
  • Ghost Article Ghost publishes photos only, so this video would not go out with the post. Send it to a channel that takes a video, or leave it off the Ghost copy of this post.
  • Tumblr Post Tumblr publishes photos only, so this video would not go out with the post. Send it to a channel that takes a video, or leave it off the Tumblr copy of this post.

The other tools

Inside the composer

The same counters run inside the composer

Postauto measures a draft against every account you have ticked before it will let you schedule anything, using the code on this page. Nothing fails at departure time over length.

Start free Every network and its rules