by Screenshot Annotator (LX AI)

Last updated: 2026-10-03

How to use Screenshot Annotator

Screenshot Annotator turns a UI description and annotation goal into a clear markup brief — arrows, blurs, and callouts planned so PMs and support writers can annotate without clutter.

Decision-support only — confirm before you publish or act.

Getting Started with Screenshot Annotator

I built this tool after watching teams waste hours debating where to place a red arrow on a screenshot. The first step is to install the browser extension or desktop client from the official release page. Once installed, open the extension panel and you will see a blank canvas ready for a UI description.

Install the extension

• Visit the release page and download the version that matches your OS.
• Run the installer and follow the prompts; no admin rights are required for the user‑level install.
• After installation, reload any open browsers so the extension registers its context menu.
• Pin the extension toolbar icon for quick access.

Create a new project

• Click the toolbar icon and select “New Annotation”.
• Give the project a short name that reflects the feature area, for example “Settings‑Panel‑Edit”.
• Choose a default canvas size that matches the target device resolution; you can override this later per screenshot.
• Set the default annotation style (arrow color, blur strength, callout font) – you can override per item later.

Load a UI screenshot

• Use the “Upload” button to bring in a PNG, JPEG, or WebP file.
• If you prefer a live capture, press the “Capture” hotkey (Ctrl+Shift+S) and drag to select the region.
• The tool stores the original image unchanged; all annotations are saved as an overlay JSON file.
• Verify that the image appears at 100 % scale; use the zoom controls if you need to inspect pixels.

Defining Annotation Goals

Before you draw anything, write down what you want the viewer to learn from the annotated image. I find it helpful to treat the goal as a short sentence that can be answered by looking at the markup.

Goal‑setting worksheet

1. State the user question: “Where do I click to change the notification sound?”
2. Identify the UI element that answers the question: the gear icon inside the Settings pane.
3. Determine the markup needed to highlight that element: a red arrow pointing to the gear, plus a callout label “Change sound”.
4. Decide if any supplemental info is required: a blur over unrelated account details to keep focus.
5. Write the goal in the annotation panel’s description field; this text travels with the exported brief.

Common goal patterns

• Bug reproduction: highlight the erroneous control and blur surrounding noise.
• Feature walk‑through: sequence of callouts that guide the user through a multi‑step flow.
• Design review: use colored arrows to indicate spacing issues and blurred areas to hide proprietary data.
• Support article: combine a blur for sensitive IDs with a bold callout that shows the exact button label.

Creating Markup Briefs

The markup brief is a machine‑readable JSON that describes every arrow, blur, and callout. I designed the format to be both human‑friendly and easy to consume by downstream scripts that generate the final PNG overlay.

Brief structure

• version – schema version, currently “1.0”.
• canvas – width and height in pixels.
• elements – array of annotation objects.
• Each element contains:
• type: “arrow”, “blur”, or “callout”.
• position: x,y coordinates for the start point (for arrows and blurs) or anchor point (for callouts).
• style: color, thickness, radius, font size, font family.
• text: only for callouts, the string to display.
• metadata: optional free‑form field for ticket IDs or reviewer names.

Generating the brief from the UI

1. After placing an annotation, click the “Save brief” button; the tool writes the JSON to the project folder.
2. You can edit the brief directly in any text editor; the extension watches the file and updates the canvas in real time.
3. Validate the brief with the built‑in linter (click the shield icon) – it reports missing fields or out‑of‑bounds coordinates.
4. Export the brief as a standalone file for sharing with designers or developers who do not have the extension.

Using the brief in automation

• Feed the JSON to an image‑processing script that renders the overlays at scale for batch screenshots.
• Integrate the brief into your CI pipeline to automatically verify that UI changes do not break existing annotation positions.
• Store briefs alongside design specs in your version‑control repository for traceability.

Applying Arrows, Blurs, and Callouts

This section walks through the concrete actions for each annotation type. I include a table that maps typical use cases to the recommended styling.

Drawing arrows

• Select the arrow tool from the toolbar.
• Click where the arrow should start, then drag to the target point; release to finalize.
• Hold Shift while dragging to constrain the line to 45‑degree increments.
• After placement, adjust the arrowhead size in the style panel; I usually set it to 8 px for screen‑capture work.
• Change the color via the hex field; I use #D32F2F for critical actions and #1976D2 for informational flows.

Applying blurs

• Choose the blur tool; the cursor becomes a circular selector.
• Click and drag to define the blur radius; the preview shows the effect in real time.
• For rectangular regions, hold Alt while dragging to snap to a box shape.
• Set the blur strength via the slider; values between 8 and 16 work well for obscuring text while preserving shape.
• Label the blur in the metadata field if you need to track why the region was obscured (e.g., “hide email”).

Adding callouts

• Select the callout tool; click where you want the tip of the callout to anchor.
• Type the label in the inline editor that appears; press Enter to commit.
• Adjust the callout box padding and corner radius in the style panel.
• Choose a font that matches your documentation style; I prefer Inter Regular at 14 px for readability.
• If the callout overlaps other annotations, drag the box away while keeping the tip anchored.

Annotation style table

Use case	Recommended arrow	Recommended blur	Recommended callout
Bug report – highlight faulty button	Solid red, 3 px width	Light blur, radius 10 px on surrounding fields	Bold label, background #FFEBEE, text #B71C1C
Onboarding flow – step indicator	Dashed blue, 2 px width	None	Rounded box, background #E3F2FD, text #0D47A1
Design critique – spacing issue	Orange, 2 px width, double‑headed	Medium blur, radius 12 px on unrelated sections	Italic label, background #FFF8E1, text #EF6C00
Support article – hide PII	None	Strong blur, radius 18 px on email and phone fields	Simple label, background #FFFFFF, text #212121

Review and Validation Workflow

Annotations are only useful if they survive scrutiny from peers, stakeholders, and automated checks. I describe the steps I follow before publishing any marked‑up image.

Peer review checklist

• Open the exported PNG alongside the original screenshot.
• Verify that each arrow points to the exact UI element described in the goal.
• Check that blurs do not obscure information needed for understanding the context.
• Ensure callout text is legible at 100 % zoom and does not exceed the box boundaries.
• Confirm that the markup brief JSON matches the visual overlays (use the “Compare brief” tool).
• Ask a teammate to read the goal statement and see if they can answer it without additional explanation.

Automated validation

• Run the built‑in validator (shield icon) which checks for:
• Coordinates outside canvas bounds.
• Overlapping callouts that hide each other.
• Arrow length shorter than 8 px (likely a mistake).
• Blur radius larger than half the shortest canvas dimension (may hide too much).
• Integrate the validator into your pre‑commit hook so bad annotations never reach the main branch.
• For teams handling sensitive data, run a privacy scan that flags any region with a blur strength below a threshold; this prevents accidental leaks.

Security and responsible‑AI considerations

When you use Screenshot Annotator in contexts that involve AI‑generated UI descriptions, it is wise to review the guidance from the OWASP Top 10 for Large Language Model Applications and the NIST AI Risk Management Framework. You can read those documents here: https://owasp.org/www-project-top-10-for-large-language-model-applications and here: https://www.nist.gov/itl/ai-risk-management-framework. These resources help you spot prompt injection risks and ensure that any automated brief generation respects fairness and transparency principles.

Final approval and publishing

1. Once the checklist passes, export the final PNG at the desired resolution (2× for Retina displays if needed).
2. Save the markup brief alongside the image in your asset repository.
3. Update the associated ticket or documentation page with the new image link.
4. Notify stakeholders via your usual channel; include a short note that the image is decision‑support only and should be confirmed before acting.
5. Archive the raw screenshot and brief for future audits.

What this is NOT

I want to be clear about the limits of this tool so you do not rely on it for things it cannot do.

• It is not a full‑blown image editor; you cannot adjust brightness, contrast, or color balance beyond the annotation overlays.
• It does not replace a professional design review process; use it to supplement, not substitute, expert critique.
• It does not guarantee that every viewer will interpret the annotations exactly as you intend; always verify with actual users.
• It is not a security scanner; the blur feature obscures pixels but does not encrypt or redact underlying data.
• It does not automatically generate UI descriptions from code; you must supply the description and goal yourself.
• It is not a substitute for legal advice; if you need to hide personal data for compliance reasons, consult your privacy officer.
• It does not promise 100 % accuracy in coordinate placement; manual checks are still required.

References

• https://owasp.org/www-project-top-10-for-large-language-model-applications
• https://www.nist.gov/itl/ai-risk-management-framework

FAQ

What is the main point of How to use Screenshot Annotator?

Screenshot Annotator turns a UI description and annotation goal into a clear markup brief — arrows, blurs, and callouts planned so PMs and support writers can annotate without clutter.

How does How to use Screenshot Annotator help?

Decision-support only — confirm before you publish or act.

Want to try the product? Screenshot Annotator

Generated 2026-09-17 · primary sources only · no fabricated traffic metrics