You inherit a landing page from someone who left. Something feels off about it: a nav link that's barely readable, a card grid where the last item drops onto its own row for no obvious reason, a hero that looks tilted even though nothing in the CSS says it is. You open DevTools, poke around for twenty minutes, and end up with a hunch instead of a fix.
Debug Screenshot is the tool for that exact moment. Capture the page, click one button, and Vzlyze returns a structured report: what it sees, what's wrong, why it's wrong, and how to fix it. This article walks through how it works, what makes it different from asking a chatbot to look at your screenshot, and where it falls short.
What Debug Screenshot does
Debug Screenshot is a Pro and Business feature. You capture any web page (region or full page), open Vzlyze, pick Debug UI from the analysis modes, and click Debug Screenshot. About ten seconds later the popup returns a plaintext report with five sections: WHAT IS SHOWN, BUGS IDENTIFIED, LIKELY ROOT CAUSES, SUGGESTED FIXES, and PRIORITY. If your page content is in French, the report comes back in French; the section titles stay in English so tooling can parse them consistently. Each run costs one Deep credit.
Where the button lives
Use the extension's Full Page or Select Area capture. Tight framing usually beats a whole page: if you already suspect a region, capture just that region and the report will focus its analysis there.
Scroll to the analysis modes. You'll see Quick, Deep, Compare, and Debug UI cards. On Free and Starter plans, the Debug UI card is dimmed with an inline Upgrade link. On Pro and Business, it's active and shows your remaining Deep credit balance.
The button flips to a working state, runs about ten seconds, and drops a structured report into the result panel. Copy it, paste it into a ticket, or hand it to a teammate. The image you captured stays in the popup, so you can re-run against the same capture or move it into the annotation editor for further work.
The trick: DOM extraction plus vision
Most "ask AI about my screenshot" workflows stop at the image. You paste a PNG into a chat window and hope the model spots something. Debug Screenshot goes further. At the moment of capture, Vzlyze walks the page's DOM and extracts up to forty computed-CSS observations before sending anything to Claude. It records whether the page has horizontal overflow (scrollWidth greater than viewportWidth is a smoking gun). It tags each suspect element with a category (layout, contrast, positioning, form) and includes the specific value that made it suspect. That structured DOM payload arrives at Claude alongside the screenshot.
The model isn't guessing what colour a nav link is. It knows the exact hex code and the exact background it's sitting on. It knows which flex container has a mismatched child count. It knows the exact pixel measurement of the overflow. Its job is to combine those numbers with what the screenshot shows and write a report a developer can act on.
That's why Debug Screenshot catches bugs a naked-eye scan misses. A button with color: #6b7280 on background: #4b5563 looks visible to a human squinting at a screenshot at 100% zoom. The DOM payload flags the contrast ratio as 2.1:1, well below the 4.5:1 WCAG AA threshold, and the report calls it out with the exact CSS to fix.
What the output looks like
Here's an illustrative example of a report on a hypothetical pricing page. Real reports match this shape exactly:
WHAT IS SHOWN: A three-column pricing page with a hero section, three plan cards, and a comparison table below the fold. BUGS IDENTIFIED: - The "Business" plan card is 24px taller than the other two, breaking horizontal grid alignment. - Nav link "Pricing" has a color contrast ratio of 2.4:1 against the header background, failing WCAG AA (4.5:1 minimum). - The comparison table's last column overflows its container by 42px on viewports below 1280px. - The "Start free trial" button has no visible focus ring, failing keyboard accessibility. LIKELY ROOT CAUSES: - The Business card contains an extra <p class="badge"> element the other cards don't; either remove it or normalise card heights. - The Pricing link inherits --nav-dim, a custom property meant for muted state but applied unconditionally. - The table uses width: 1200px without overflow-x: auto on wrapper. - Global focus-visible outline is being reset by a rule in reset.css. SUGGESTED FIXES: - .plan-card { min-height: 480px; } to enforce equal height. - .nav-link { color: #d1d5db; } (raises contrast to 5.2:1). - .comparison-table-wrapper { overflow-x: auto; } and drop fixed width. - Add :focus-visible { outline: 2px solid #6366f1; } to interactive elements. PRIORITY: Fix contrast first (accessibility failure, EU legal exposure). Card height second (most visible aesthetic bug). Table overflow third (only affects narrow viewports). Focus ring last, but before ship.
Five sections, always. Bugs pointed to specific selectors, not vague adjectives. Fixes given as CSS you can paste. Priority ranked by severity, not by order of discovery.
The checklist under the hood
The prompt gives Claude an exhaustive checklist to walk through before writing anything. This is deliberate: models otherwise pattern-match to the most obvious issue and stop. The checklist forces coverage of the categories that developers systematically miss when reviewing their own work:
- Text overflow (text visibly cut off or spilling outside its container)
- Grid and flex issues (column mismatches, orphaned items, uneven cards, items bunching to one side)
- Colour contrast (text or interactive elements with insufficient contrast against their background)
- Table issues (overflowing columns, clipped content, missing row striping)
- Positioning bugs (elements overlapping, bleeding outside parent bounds, badges in wrong position)
- Form issues (misaligned labels, inconsistent input widths, invisible submit buttons)
- Invisible or near-invisible elements that should be visible
- Loading spinners left permanently on-screen
- Z-index problems (elements hidden behind siblings or parents)
- Spacing anomalies (excessive padding or margin creating unexplained empty areas)
The prompt closes with an explicit instruction: do not skip anything because it looks intentional. Report it. Let the developer decide.
Where it falls short
Debug Screenshot is a vision-plus-DOM audit. It's good at what it can see. There are bugs it will miss.
State-dependent bugs. A dropdown that breaks only when opened, a hover state that reveals a broken tooltip, a form validation flash that appears for half a second: none of those show up in a static capture. Capture the broken state, not the resting one.
Runtime and console bugs. JavaScript errors, memory leaks, network requests that fail silently, race conditions: none of these live in a screenshot or in a DOM snapshot. Use Chrome DevTools for those. Use Debug Screenshot for what your eye can almost see but not quite.
Cross-browser issues. Vzlyze captures whatever Chrome renders. If your bug reproduces only in Safari or Firefox, capture the bug in the browser where it appears, paste that screenshot into Vzlyze, and note the browser in the analysis. The DOM payload will be missing (Vzlyze can only walk the current tab's DOM), but the visual pass still applies.
Design intent. The report flags anything that looks off. Sometimes what looks off is a deliberate choice: a hero that's asymmetric on purpose, a card that's larger because it's featured, a button style that ignores WCAG because the page has a special contrast toggle elsewhere. Read the report critically. It's a second pair of eyes, not a code owner.
Try Debug Screenshot
Available on Pro and Business. Costs one Deep credit per run. No setup, no config, no waiting for a review cycle.
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