# VerificationVerify Thulite Images by inspecting generated HTML, transformed assets, and browser behavior to confirm responsive, optimized output. This guide helps you verify that Thulite Images is rendering optimized image markup and generated assets as expected. ## Inspect generated HTML View page source in your browser and confirm that image markup is generated correctly. Check for: - `` and/or `` output where expected - `srcset` and `sizes` attributes for responsive images - `loading`, `decoding`, and `fetchpriority` attributes according to your settings - `alt` text on all content images - Width and height attributes to reduce layout shift If you use fallback formats, also verify that generated `` elements (for example WebP) are present in `` markup. {{< details "Example (excerpt)" >}} ```html A small bird perched on top of a tree branch ``` {{< /details >}} ## Inspect generated image assets Build your site and confirm that transformed files are generated. Check for: - Multiple widths for responsive variants - Expected output formats (for example WebP with JPEG/PNG fallback) - LQIP output when configured - File sizes that match your quality and compression settings You can inspect the generated assets in your build output and compare dimensions and file size across variants. ## Validate in the browser Open your pages in DevTools and verify image behavior in real conditions. Check for: - Correct candidate selection from `srcset` at different viewport widths - Lazy loading behavior below the fold - No 404 responses for generated image URLs - No unexpected layout shifts caused by image rendering ## Use tools Use external tools to validate image quality and performance impact. For example: - [Lighthouse](https://developer.chrome.com/docs/lighthouse/overview) - [PageSpeed Insights](https://pagespeed.web.dev/) - [WebPageTest](https://www.webpagetest.org/) If anything looks incorrect, continue to the [Troubleshooting](/docs/start-here/troubleshooting/) guide.