- A
Set the trigger's 'source' parameter to 'EventGrid' and filter events by the 'content-type' property.
Why wrong: Blob trigger with EventGrid source can filter by event type, but not directly by content-type.
- B
Set the trigger's 'filter' property to '*.jpg,*.png'.
Why wrong: The blob trigger does not support a filter property.
- C
Implement the function without filtering and check the content type inside the function, ignoring non-image blobs.
Why wrong: This works but is less efficient; however, the question asks for the best approach, and filtering at trigger level is not possible, so this is often the practice. But option B is more precise.
- D
Use the blob trigger with a path pattern like 'images/{name}.jpg' and 'images/{name}.png' and use the extension binding to filter.
You can create separate functions for each extension or use a pattern and check the extension in code.
Quick Answer
The correct approach is to use the blob trigger with a path pattern like `images/{name}.jpg` and `images/{name}.png`, leveraging the extension binding to filter by file extension. This works because Azure Functions blob triggers support declarative path patterns that match on the blob name, including its extension, so the function only fires when a blob with a matching extension is created in the specified container—no runtime code or additional services are needed to ignore non-image files. On the AZ-204 exam, this tests your understanding of trigger configuration versus runtime filtering; a common trap is writing C# or JavaScript code to check the file extension inside the function, which wastes execution time and cost. Remember that the path pattern itself is the filter—think of it as a declarative gatekeeper. Memory tip: “Pattern first, code second”—always configure the extension in the trigger path before writing any logic.
AZ-204 Develop for Azure storage Practice Question
This AZ-204 practice question tests your understanding of develop for azure storage. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
You are developing a web application that allows users to upload profile pictures to Azure Blob Storage. The application generates thumbnails using an Azure Function that is triggered by blob creation. You need to ensure that the function only processes image files and ignores other file types. What should you do?
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
Use the blob trigger with a path pattern like 'images/{name}.jpg' and 'images/{name}.png' and use the extension binding to filter.
Option D is correct because Azure Blob Storage triggers in Azure Functions support path patterns that filter on blob name extensions, such as 'images/{name}.jpg' and 'images/{name}.png'. This allows the function to only fire when a blob with a matching extension is created, effectively ignoring non-image files without any runtime code or additional services.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Set the trigger's 'source' parameter to 'EventGrid' and filter events by the 'content-type' property.
Why it's wrong here
Blob trigger with EventGrid source can filter by event type, but not directly by content-type.
- ✗
Set the trigger's 'filter' property to '*.jpg,*.png'.
Why it's wrong here
The blob trigger does not support a filter property.
- ✗
Implement the function without filtering and check the content type inside the function, ignoring non-image blobs.
Why it's wrong here
This works but is less efficient; however, the question asks for the best approach, and filtering at trigger level is not possible, so this is often the practice. But option B is more precise.
- ✓
Use the blob trigger with a path pattern like 'images/{name}.jpg' and 'images/{name}.png' and use the extension binding to filter.
Why this is correct
You can create separate functions for each extension or use a pattern and check the extension in code.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume you must check the content type inside the function (Option C) because they think blob triggers cannot filter by extension, but Azure Functions actually support path pattern filtering on the trigger binding itself.
Detailed technical explanation
How to think about this question
Under the hood, the Blob trigger uses an Azure Storage queue to monitor blob creation events; the path pattern is evaluated at the trigger level before the function is invoked, meaning non-matching blobs never trigger the function, reducing cold starts and costs. A subtle behavior is that the pattern 'images/{name}.jpg' matches blobs with exactly that extension, but it does not support multiple extensions in a single binding; you must create separate function bindings or use a single pattern like 'images/{name}.{ext}' and then check the extension inside the function if you need to handle multiple types. In a real-world scenario, using path filtering is critical for high-throughput systems where processing every blob creation event would overwhelm the function or incur unnecessary costs.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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Develop for Azure storage — study guide chapter
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Develop for Azure storage practice questions
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FAQ
Questions learners often ask
What does this AZ-204 question test?
Develop for Azure storage — This question tests Develop for Azure storage — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use the blob trigger with a path pattern like 'images/{name}.jpg' and 'images/{name}.png' and use the extension binding to filter. — Option D is correct because Azure Blob Storage triggers in Azure Functions support path patterns that filter on blob name extensions, such as 'images/{name}.jpg' and 'images/{name}.png'. This allows the function to only fire when a blob with a matching extension is created, effectively ignoring non-image files without any runtime code or additional services.
What should I do if I get this AZ-204 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
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.
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