Uploads & Media
Accepted file types, size limits, video requirements, and upload failures
Everything here applies to attaching media in the composer and to the Media library.
Accepted file types
| Type | Formats |
|---|---|
| Images | JPEG, PNG, GIF, WebP, AVIF, BMP, TIFF |
| Video | MP4 |
Anything outside this list is rejected on upload.
PDFs cannot be uploaded. The only PDF a post can carry is a LinkedIn document carousel, which Postaryx produces for you by converting an image carousel — you attach the images, not a PDF.
Size limits
A single upload is capped at 10 MB for images and 1 GB for video. A post's attachments are capped together as well, so a set of large images can fail even when each one is under the image limit.
If a post fails to save with a size error, replace the largest attachment with a smaller export rather than trimming the others.
"Failed to load video metadata"
Postaryx inspects an uploaded video for duration, dimensions and codec before passing it to the platform. Files outside the supported range fail at this point rather than at publish time.
Recommended video format
- Container: MP4
- Video codec: H.264, baseline or main profile
- Audio codec: AAC
- Frame rate: 30 fps or less
- Resolution: 1920×1080 or smaller for most platforms; TikTok and YouTube Shorts prefer portrait 1080×1920
Other formats may upload successfully and still be rejected by the platform afterwards, which surfaces as a failed post rather than a failed upload. See Posting rules by platform for the per-platform limits.
"uploader plugin does not allow removing files during an upload"
You pressed Cancel on a file that had already started uploading. The uploader does not support cancelling mid-flight: wait for it to finish, then remove the attachment from the post.
This is a known limitation, see Known Issues.
An upload starts and then stalls
Usually the connection rather than the file.
- Retry on a stable connection. Large video over a flaky network is the most common cause.
- Try a different browser, or a private window, to rule out an extension interfering with the upload.
- If one specific file always fails and others succeed, re-export it. A file
with a mismatched extension — a PNG saved as
.jpg— is read by its real contents, and renaming it does not help.