Question 577 of 988
CLF-C02 Cloud Technology and Services Practice Question
A company has a web application that processes user-uploaded images. When a user uploads an image, the application needs to resize the image into multiple formats (thumbnail, medium, large). The company wants to avoid managing servers and wants the image processing to execute only when a new image is uploaded. The solution must automatically scale to handle thousands of concurrent uploads. Which AWS service should the company use to perform the image processing?
⚠ Common exam trap
Test-takers frequently choose Amazon ECS with Fargate because it is also serverless, but they overlook that Lambda is the simpler, event-driven, and cost-effective service for short-lived, stateless processing tasks triggered by S3 events.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
AWS Lambda
AWS Lambda is the correct choice because it is a serverless compute service that runs code in response to events, such as an image upload to Amazon S3. It automatically scales from zero to thousands of concurrent executions, perfectly matching the requirement to avoid managing servers and to process images only when a new upload occurs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Amazon EC2 Auto Scaling group
Why it's wrong here
EC2 Auto Scaling groups manage the number of EC2 instances, but they require ongoing server management and are not inherently event-driven to respond to individual image uploads. Using EC2 for this task would involve unnecessary overhead and cost.
When this WOULD be correct
A company needs to run a stateful, long-running application (e.g., a web server with persistent connections) that must scale based on CPU utilization or request count, and is willing to manage server instances (e.g., patching, monitoring).
- ✓
AWS Lambda
Why this is correct
AWS Lambda is a serverless compute service that runs code in response to triggers, such as an S3 upload event. It scales automatically and charges only for execution duration, making it perfect for short-lived, sporadic image processing tasks.
- ✗
Amazon ECS with Fargate launch type
Why it's wrong here
While Amazon ECS with Fargate is serverless and can run containers, it is not as straightforward or cost-effective for simple, event-driven image resizing. ECS is more suited for long-running or batch container workloads, not for instantly responding to individual events.
When this WOULD be correct
A company needs to run a long-running image processing task that exceeds Lambda's 15-minute timeout, or requires a custom runtime or GPU acceleration not supported by Lambda. In such cases, ECS with Fargate would be the correct choice for serverless containerized processing.
- ✗
AWS Elastic Beanstalk
Why it's wrong here
Elastic Beanstalk is a platform as a service (PaaS) that automates the deployment and scaling of applications on managed servers. It requires a continuously running application environment and is not designed to execute code only in response to specific events like image uploads.
When this WOULD be correct
A company wants to deploy a web application with automatic scaling, load balancing, and monitoring, but needs to maintain control over the underlying EC2 instances and environment configuration. Elastic Beanstalk would be correct for deploying the full application stack, not just event-driven processing.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The CLF-C02 exam frequently reuses these exact scenarios with slightly different constraints.
✓AWS LambdaCorrect answer▾
Why this is correct
AWS Lambda is a serverless compute service that runs code in response to triggers, such as an S3 upload event. It scales automatically and charges only for execution duration, making it perfect for short-lived, sporadic image processing tasks.
✗Amazon EC2 Auto Scaling groupWrong answer — click to see why▾
Why this is wrong here
Amazon EC2 Auto Scaling requires managing servers and does not execute code only when triggered by uploads; it maintains a fleet of instances, incurring cost even when idle, and does not natively respond to S3 events for image processing.
★ When this WOULD be the correct answer
A company needs to run a stateful, long-running application (e.g., a web server with persistent connections) that must scale based on CPU utilization or request count, and is willing to manage server instances (e.g., patching, monitoring).
Why candidates choose this
Candidates know Auto Scaling can handle variable workloads, but they overlook the requirement to avoid server management and the need for event-driven, short-lived processing triggered by uploads.
✗Amazon ECS with Fargate launch typeWrong answer — click to see why▾
Why this is wrong here
Amazon ECS with Fargate requires container orchestration and incurs costs even when idle, whereas AWS Lambda is serverless, event-driven, and scales automatically only when triggered by image uploads, making it more cost-effective and simpler for this use case.
★ When this WOULD be the correct answer
A company needs to run a long-running image processing task that exceeds Lambda's 15-minute timeout, or requires a custom runtime or GPU acceleration not supported by Lambda. In such cases, ECS with Fargate would be the correct choice for serverless containerized processing.
Why candidates choose this
Candidates may think that image processing is too complex for Lambda and requires a containerized solution, or they may be familiar with ECS for batch processing and overlook Lambda's suitability for event-driven, short-lived tasks.
✗AWS Elastic BeanstalkWrong answer — click to see why▾
Why this is wrong here
AWS Elastic Beanstalk is a PaaS service that manages servers and requires ongoing infrastructure, contradicting the requirement to avoid managing servers. It is not event-driven and would not automatically scale only when images are uploaded.
★ When this WOULD be the correct answer
A company wants to deploy a web application with automatic scaling, load balancing, and monitoring, but needs to maintain control over the underlying EC2 instances and environment configuration. Elastic Beanstalk would be correct for deploying the full application stack, not just event-driven processing.
Why candidates choose this
Candidates may think Elastic Beanstalk can handle the processing because it supports web applications and auto-scaling, but they overlook that it still manages servers and is not designed for event-driven, stateless processing tasks triggered by uploads.
Analysis generated from the official CLF-C02blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
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Last reviewed: Jun 11, 2026
This CLF-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CLF-C02 exam.
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