Images uploaded to S3 must be resized. Work is bursty — zero to thousands of uploads per hour — and each resize finishes in seconds. Which compute option is the best operational fit?
A.A large always-on EC2 instance
An always-on instance idles during quiet periods and can be overwhelmed at peak.
B.AWS Lambda triggered by S3 event notifications
Correct. Event-triggered Lambda matches bursty, short-lived workloads.
C.A cron job on a t3.micro polling for new files each hour
Hourly polling adds up to an hour of latency and wasted cycles.
D.Amazon ECS with a fixed cluster of one task
A fixed one-task cluster cannot absorb bursts and still runs when idle.
Why this answer
Lambda scales automatically from zero to thousands of concurrent invocations, bills only for actual compute time, and integrates natively with S3 event notifications — ideal for short, bursty, event-driven work.
Correct answer: B · Last reviewed 2026-10-25
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