SAA-C03 Q589 · Serverless

Question

A company runs an application that stores and shares photos. Users upload photos to an Amazon S3 bucket. Approximately 150 photos are uploaded daily. The company wants to create a thumbnail for each new photo and store it in a second S3 bucket. Which solution will meet these requirements MOST cost-effectively?

Accepted Answer

**Option C: S3 event notification → Lambda function** is correct because it perfectly matches every requirement:

1. **Event-driven processing**: S3 event notifications can trigger a Lambda function automatically whenever a new object (photo) is uploaded (`s3:ObjectCreated:*` event). No polling or scheduling needed.

2. **Cost-effectiveness**: With ~150 photos/day, Lambda is extraordinarily cheap. Each invocation runs only for the few seconds needed to generate a thumbnail. You pay only for the compute time used — likely pennies per day. There is no idle infrastructure.

3. **Real-time processing**: Thumbnails are generated immediately after upload, providing a better user experience compared to batch/scheduled approaches.

4. **No infrastructure management**: Lambda is fully managed — no

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💰 Cost

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