> ## Documentation Index
> Fetch the complete documentation index at: https://docs.letmepost.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# bluesky.media.image_size_max

> Each image must be ≤ 976 KB (1,000,000 bytes). Bluesky's blob limit.

## What it checks

`byteLength <= 1_000_000` per image item.

## Why

Bluesky's PDS blob upload caps at \~976 KB (1,000,000 bytes — Bluesky uses base-10, not base-2). Larger blobs are rejected with `BlobTooLarge`. The 976 KB number is the "post" you want; the constant is the byte limit you should compare to.

## Failure response

```json theme={"system"}
{
  "error": {
    "code": "preflight_failed",
    "rule": "bluesky.media.image_size_max",
    "platform": "bluesky",
    "message": "Image is 1450000 bytes; Bluesky allows at most 1000000.",
    "remediation": "Re-encode the image under 1000000 bytes (Bluesky's blob limit is ~976 KB)."
  }
}
```

## Remediation

Re-encode at lower quality or smaller dimensions. For JPEGs, quality 80–85 + max-dimension 2048 px is usually enough.

```sh theme={"system"}
# ImageMagick
magick input.jpg -quality 82 -resize 2048x2048\> output.jpg

# sharp (Node)
await sharp(input).resize({ width: 2048, withoutEnlargement: true }).jpeg({ quality: 82 }).toFile("output.jpg");
```

## Related

* [`bluesky.media.video_size_max`](/preflight/bluesky-media-video_size_max)
* [`bluesky.media.mime_allowed`](/preflight/bluesky-media-mime_allowed)