Camera Snapshots

Cameras are just devices. A snapshot is a JPEG or PNG image uploaded via HTTP; its URL is stored alongside your telemetry data. There is no separate video subsystem - snapshots are event-driven images tied to your existing device workflow.

Use cases include security cameras capturing motion events, machine-vision boards inspecting products on a conveyor, wildlife cameras triggered by PIR sensors, and agricultural monitors checking crop health.

How It Works

┌────────────────┐                            ┌──────────────────┐
│  Camera Device │                            │  SiliconWit.IO   │
│  (ESP32-CAM,   │  1. POST image bytes       │                  │
│   Raspberry Pi,│ ──────────────────────────► │  /api/devices/   │
│   etc.)        │  2. Get back snapshot URL   │  {id}/snapshot   │
│                │ ◄────────────────────────── │  (cloud storage) │
│                │                            │                  │
│                │  3. MQTT telemetry with     │  Dashboard       │
│                │     snapshot_url field      │  renders         │
│                │ ──────────────────────────► │  thumbnail       │
└────────────────┘                            └──────────────────┘

1. Your device captures an image and sends the raw bytes via HTTP POST
2. SiliconWit.IO stores the image and returns a public CDN URL
3. Your device includes that URL in its next MQTT telemetry message
4. The dashboard renders the URL as a clickable thumbnail

API Reference

Upload a Snapshot

POST /api/devices/{device_id}/snapshot

Headers:

Header	Value	Required
Authorization	Bearer YOUR_ACCESS_TOKEN	Yes
Content-Type	image/jpeg or image/png	Yes

Body: Raw image bytes (max 500 KB)

Success Response (200):

{
  "success": true,
  "url": "https://cdn.siliconwit.io/snapshots/{device_id}/{id}.jpg",
  "id": "a1b2c3d4-..."
}

Error Responses:

Status	Meaning	Common Cause
400	Bad Request	Missing device ID, unsupported content type, empty body
401	Unauthorized	Missing or invalid access token
403	Forbidden	Device is paused
413	Payload Too Large	Image exceeds 500 KB
429	Too Many Requests	Daily snapshot limit reached
503	Service Unavailable	Storage backend temporarily unavailable

Including the URL in Telemetry

After uploading, include the returned URL in your MQTT telemetry payload:

{
  "temperature": 23.5,
  "snapshot_url": "https://cdn.siliconwit.io/snapshots/{device_id}/{id}.jpg"
}

The dashboard automatically detects fields ending in _url that point to image files and renders them as clickable thumbnails.

Plan Limits

Plan	Snapshots per Day	Data Retention
Free	10	7 days
Starter	50	90 days
Business	200	1 year
Scale	500	2 years
Enterprise	Admin-set	Custom

The daily limit resets on a rolling 24-hour window. If you hit the limit, the API returns 429 Too Many Requests.

Quick Test with curl

Upload a test image from your terminal:

curl -X POST "https://siliconwit.io/api/devices/YOUR_DEVICE_ID/snapshot" \
  -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
  -H "Content-Type: image/jpeg" \
  --data-binary @photo.jpg

Then publish telemetry with the returned URL:

mosquitto_pub \
  -h mqtt.siliconwit.io \
  -p 8883 \
  --capath /etc/ssl/certs \
  -u "YOUR_DEVICE_ID" \
  -P "YOUR_ACCESS_TOKEN" \
  -t "d/YOUR_DEVICE_ID/t" \
  -m '{"snapshot_url": "https://cdn.siliconwit.io/snapshots/YOUR_DEVICE_ID/abc123.jpg"}'

Dashboard Display

Snapshot URLs in telemetry appear in two places:

• Latest Reading panel - shows a thumbnail of the most recent snapshot
• Data table - each row with a snapshot URL shows a clickable thumbnail that opens the full image

No extra configuration is needed. Any telemetry field whose value is a URL pointing to an image on cdn.siliconwit.io is automatically rendered as a thumbnail.

Data Retention

Snapshots follow the same retention rules as your telemetry data. When the retention period expires:

1. A warning email is sent with a 3-day grace period
2. After the grace period, expired snapshots are deleted from both storage and the database

Upgrading your plan extends the retention period for all existing data, including snapshots.

Tip

To avoid losing important snapshots, download them before the retention period expires. You can use the snapshot URL directly to save the image.

Tips

• Use JPEG for photos. JPEG files are typically 5-10x smaller than PNG for photographic content, keeping you well under the 500 KB limit.
• Resize before uploading. A 640x480 JPEG at 80% quality is usually under 100 KB - plenty for event monitoring.
• Add motion detection. Capture only when something changes rather than on a fixed timer. This conserves your daily quota and makes the data more meaningful.
• Include context fields. Send additional telemetry alongside the snapshot URL (temperature, motion score, timestamp) to make each event searchable and alertable.

Next Steps

• ESP32-CAM Snapshots Tutorial - Full Arduino + Python walkthrough
• Topics & Payloads - MQTT message format reference
• Dashboard Alerts - Trigger alerts based on telemetry values