Social media image size and aspect ratio requirements

YouTube, Nostr and Slack have no image posting in these constants. Slack connections accept text only, YouTube is video, and Nostr is text. "n/a in constants" means Socifyr does not carry a number for that field, so check the platform's own documentation before relying on one.

Instagram feed images must be between 4:5 portrait (0.8) and 1.91:1 landscape. Socifyr enforces that window before publishing. An image already inside it goes out as uploaded. An image that is too wide is center-cropped to 1.91:1, and one that is too tall is center-cropped to 4:5, then saved as a JPEG at quality 92. The crop happens on a temporary copy, so your original in the media library is untouched.

If composition matters, crop images yourself. A story-format 1080x1920 image posted to the feed loses a large strip of the top and bottom. For Stories, upload the image or video as a Story rather than a feed post; see how to post to Instagram via API.

Bluesky rejects image blobs of 1,000,000 bytes or more at record creation, which is stricter than almost any other platform. Socifyr passes images under the limit through untouched and re-encodes bigger ones as a JPEG with shrinking dimensions and quality until they fit under about 976 KB. So you can send the same 4 MB photo to Instagram and Bluesky, and each platform gets a file that fits. Details in the Bluesky and Mastodon guide.

The smallest per-file limit in your set decides the practical maximum. For Instagram, Facebook, Threads, LinkedIn and Mastodon that is 8 MB, and Bluesky shrinks its own copy. The smallest carousel limit decides how many images a shared post can carry: 4 if X, Bluesky or Mastodon are in the set, 5 with Pinterest, and 1 with Reddit or Tumblr.

import { getEffectiveCarouselLimit, getEffectivePhotoSizeLimit } from '@socifyr/shared'

const targets = ['instagram', 'x', 'bluesky'] as const

getEffectiveCarouselLimit([...targets])  // 4  (X and Bluesky)
getEffectivePhotoSizeLimit([...targets]) // 1  (Bluesky, in MB)

await socifyr.uploads.photos({
  connections: ['instagram-mybrand', 'x-myhandle', 'bluesky-mybrand'],
  medias: ['https://cdn.example.com/a.jpg', 'https://cdn.example.com/b.jpg'],
  text: 'Two photos, three platforms',
})

curl -X POST https://api.socifyr.com/api/content/photos \
  -H "Authorization: Bearer sk_your_key" \
  -H "X-Workspace-Id: <workspaceId>" \
  -F "connections[]=instagram-mybrand" \
  -F "connections[]=facebook-mypage" \
  -F "medias[]=@photo1.jpg" \
  -F "medias[]=@photo2.jpg"

You can mix raw files with media library IDs and public URLs. The photos endpoint accepts up to 10 files per request. Uploaded files also count toward your workspace storage (1 GB free, 50 GB Pro, 500 GB Business).

Socifyr maps the platform's raw message to a readable one. For an oversized file the reason is that the media file is too large for that platform, and the hint lists the platform's own limits, for example video 300 MB and image 8 MB for Instagram. For a bad ratio or resolution the reason says the media does not meet the platform's format requirements and tells you to check the aspect ratio, resolution or duration. Replace the file before retrying, because the same file will fail again.

1. List the platforms the carousel goes to and take the smallest carousel limit. With Instagram and Threads only, that is 10. Add X, Bluesky or Mastodon and it drops to 4.
2. Export at the recommended size of your most important platform, for example 1080x1350 for Instagram, which sits at the 4:5 edge of its range.
3. Keep each file under 8 MB so it clears Instagram, Threads, LinkedIn, Discord and Mastodon.
4. Use JPG. It is accepted by every platform in the table (PNG is accepted by all except TikTok photo posts, which take JPG and WebP).
5. Keep important content away from the edges in case a platform crops.

Mixed photo and video carousels are allowed on Instagram, Threads and Telegram in the shared constants. Facebook, Pinterest, X, Bluesky, Mastodon and Discord galleries are single-media-type.