# Media & Images · PostLake Docs

> Markdown version of https://docs.postlake.dev/media . The canonical page for humans.
> PostLake is the social media API for AI agents: https://postlake.dev/llms.txt

Upload media once to get an id, then attach it to a post. Each network has its own limits. A media set that isn't valid for one target fails just that target.

## Upload

POST the raw bytes with the correct `Content-Type`. You get back a `MediaAsset`.

```
curl -X POST https://api.postlake.dev/v1/media \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: image/jpeg" \
  --data-binary @photo.jpg
```

```
{ "id": "med_abc", "url": "https://…", "contentType": "image/jpeg", "size": 208134 }
```

**Supported:** JPEG, PNG, WebP images; MP4 video. Video-only networks (YouTube, TikTok) require a video asset.

## Attach. Globally or per platform

Put ids in `media` to attach to every account, or use `mediaOverrides` to give each platform its own set (a square image for Instagram, a video for TikTok).

```
{
  "text": "Launch day",
  "media": ["med_abc"],
  "mediaOverrides": { "tiktok": ["med_video"] },
  "accounts": ["acc_ig", "acc_tt"]
}
```

## Per-platform media limits

| Platform | Media |
| --- | --- |
| **Bluesky** | Up to 4 images, or 1 video |
| **Threads** | Image carousel, or video |
| **Instagram** | Image or video (Reels) |
| **TikTok / YouTube** | Video only |
| **X, LinkedIn, Facebook** | Images and video |
| **Pinterest** | Image or video (needs a `boardId`) |

These are the practical rules today; call `GET /v1/platforms/{platform}` for the live, authoritative limits (max count, size, aspect) so you, or an agent, can validate before posting.

## Alt text

Provide accessibility alt text per media item through `platformOptions` / media alt overrides. If a media set is invalid for a target, that target fails with a clear `error` and the others still publish, see [Errors](https://postlake.dev/errors).