AZ-204 Develop Azure compute solutions Practice Question
You are designing a solution to process thousands of images uploaded to Azure Blob Storage. Each image must be resized and metadata extracted. The processing must be serverless and cost-effective. Which Azure service should you use?
⚠ Common exam trap
Test-takers frequently choose Azure Event Grid (Option C) because it is event-driven, but they overlook that Event Grid alone does not provide compute; it requires a separate compute service (like Functions or a webhook) to process the image, and the question specifically asks for a serverless and cost-effective solution that directly processes the images, which Azure Functions with a Blob Storage trigger achieves natively.
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
✓
Azure Functions with Blob Storage trigger
Azure Functions with a Blob Storage trigger is the correct choice because it provides a serverless, event-driven compute model that automatically scales to process thousands of images as they are uploaded to Blob Storage. The trigger binds directly to a blob container, invoking a function for each new blob, which allows you to resize images and extract metadata without managing infrastructure, making it both cost-effective and efficient for high-throughput workloads.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Azure Container Instances with Blob Storage SDK
Why it's wrong here
Azure Container Instances (ACI) provides a fast way to run containers, but it is not inherently event-driven for Blob Storage. To process new image uploads, an application within ACI would need to implement a continuous polling mechanism to check for new blobs, which is inefficient and introduces latency. This approach lacks the automatic scaling and cost-efficiency of a truly event-driven serverless solution for high-volume processing.
- ✗
Azure Logic Apps with Blob Storage connector
Why it's wrong here
While Azure Logic Apps can be triggered by Blob Storage events, they are better suited for workflow orchestration and integration tasks rather than high-volume, custom image processing. Their consumption-based pricing model can become significantly more expensive for thousands of images compared to serverless compute. Furthermore, implementing complex, custom image manipulation logic directly within Logic Apps is less flexible and often requires integrating with external compute services, adding complexity.
- ✗
Azure Event Grid with Webhook to a custom service
Why it's wrong here
Azure Event Grid efficiently delivers event notifications for Blob Storage uploads to a specified webhook endpoint. However, Event Grid is purely an event routing service and does not provide any compute capabilities itself for processing the images. The "custom service" receiving the webhook would still need to be separately provisioned, managed, and scaled to handle the image processing workload, introducing additional operational overhead and complexity.
- ✓
Azure Functions with Blob Storage trigger
Why this is correct
Azure Functions with a Blob Storage trigger offers an ideal serverless solution for processing thousands of images efficiently. It automatically executes custom code in response to new blob uploads, providing a truly event-driven architecture. This approach scales elastically with demand, only charging for the compute resources consumed during processing, making it highly cost-effective and eliminating the need to manage underlying infrastructure.
Quick reference
Azure Blob Storage Tier Comparison
| Tier | Storage Cost | Retrieval Cost | Latency | Use Case |
|---|---|---|---|---|
| Hot | Highest | Lowest | Immediate | Active data, frequent reads |
| Cool | Lower | Higher | Immediate | Data accessed < once / month |
| Cold | Lower still | Higher | Immediate | Data accessed < once / quarter |
| Archive | Lowest | Highest + rehydration delay | Hours | Long-term compliance retention |
Go deeper
Related to this question
Learn chapter
Azure Functions Development
Key term
Durable Functions
Durable Functions is an extension of Azure Functions that lets you write stateful workflows in code, managing complex sequences of tasks, retries, and delays automatically.
Key term
Azure Functions Bindings
Azure Functions Bindings are declarative connections that link your serverless function code to Azure services or external resources, handling input and output data automatically without writing extra networking or authentication code.
About these practice questions
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-204 practice question is part of Courseiva's free Microsoft 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 AZ-204 exam.