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Documentation Index

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What it checks

The IG container reports an aspect-ratio rejection when the media’s width/height ratio is outside 0.8..1.91 for feed posts, or not 9:16 for Reels. Detection happens at the container status-poll step — preflight surfaces the rule when Meta reports it.

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Why we don’t check it statically

Verifying the aspect ratio requires reading image dimensions or ffprobe-style video introspection. We don’t do that in the API hot path; instead we let Meta run its own check and translate the response into this rule.

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Failure response

{
  "error": {
    "code": "preflight_failed",
    "rule": "instagram.media.aspect_ratio",
    "platform": "instagram",
    "message": "Instagram rejected the container — media aspect ratio is outside the accepted range.",
    "remediation": "Crop or pad to a 4:5..1.91:1 ratio for feed posts, or 9:16 for Reels."
  }
}

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Remediation

For a feed image, the safest target is 1:1 (1080×1080). Reels: 9:16 (1080×1920). 
# Pad a wide image to 1:1
magick input.jpg -gravity center -background white -extent 1080x1080 output.jpg

# Crop a 16:9 video to 9:16
ffmpeg -i input.mp4 -vf "crop=ih*9/16:ih,scale=1080:1920" -c:a copy output.mp4