Paste your page HTML and instantly audit every image for issues that hurt SEO and Core Web Vitals: missing alt text, generic filenames, missing dimensions, lazy loading problems, and outdated formats.
9 Checks
Per Image
Alt Text
Analysis
CWV
LCP + CLS
Private
No Uploads
Your HTML is analyzed locally in your browser. Nothing is sent to any server.
Open your page in a browser.
Right-click anywhere on the page and choose View Page Source (or press Ctrl+U on Windows, Cmd+U on Mac).
Select all and copy (Ctrl+A then Ctrl+C), then paste the HTML into the checker above. You can also paste just the relevant section containing your images rather than the full page.
Click Run check. Results appear instantly, grouped by image with a severity breakdown for each issue found.
Expand each image row to read the specific issue and the recommended fix. Prioritize Errors first, then Warnings, then Suggestions.
An img element with no alt attribute at all is both an SEO gap and an accessibility failure. Google cannot classify the image and screen readers announce it as a nameless image. Every img must have an alt attribute, even if it is empty for decorative images.
Without explicit dimensions, the browser cannot reserve space for the image before it loads. The layout shifts when the image arrives, increasing your Cumulative Layout Shift (CLS) score, which is one of Google's Core Web Vitals metrics used as a ranking signal.
Filenames like IMG_1234.jpg, DSC_0032.jpg, image1.png or screenshot.png carry no descriptive value for search engines. Google uses filenames as one of the signals to understand image content. Descriptive, hyphen-separated filenames are a direct SEO improvement.
alt="" is correct for purely decorative images (dividers, background shapes). But if the image carries meaning or context for the user, empty alt wastes an SEO and accessibility opportunity. The tool flags this as a warning since intent cannot be determined from HTML alone.
A common mistake is setting alt to the image filename: alt="IMG_1234.jpg" or alt="product-photo.png". This is no more useful than an empty alt from Google's perspective and reads nonsensically to screen reader users.
Alt text shorter than 5 characters is almost certainly not meaningful. Alt text longer than 125 characters exceeds what most screen readers will announce fully, and search engines prefer concise descriptions. The recommended range is one or two descriptive sentences.
The first image on most pages is the hero banner or featured image, which is typically the Largest Contentful Paint (LCP) element. Lazy-loading it tells the browser to delay loading the most important above-fold content, directly increasing LCP time and hurting Core Web Vitals.
Images below the fold load unnecessarily on the initial page paint without lazy loading. Adding loading="lazy" defers them until the user scrolls close, reducing initial load time and bandwidth, especially on mobile connections.
BMP is an uncompressed format that produces very large files with no quality advantage. GIF as a static image is significantly larger than WebP or AVIF at equivalent quality. Both WebP and AVIF are now supported by all modern browsers and offer 25 to 50 percent smaller file sizes.
Open your page in a browser, right-click anywhere and choose View Page Source, then copy the entire HTML or just the section that contains your images. You can also paste just the relevant img tags directly, without the full page HTML. The tool only reads img elements and ignores everything else.
Google uses alt text alongside its computer vision algorithms and the surrounding page content to understand what an image shows and what topic it supports. Missing or vague alt text means Google has less signal to classify the image, reducing its chances of appearing in Google Images and weakening the relevance signal it provides to the surrounding page. Alt text also serves screen readers, making it a legal accessibility requirement under laws like the ADA, Section 508 and the European Accessibility Act.
When a browser loads a page, it needs to know how much space to reserve for each image before the image file arrives. Without explicit width and height attributes, the browser renders the page without that space, then shifts the layout when the image loads. This is called Cumulative Layout Shift (CLS) and it is one of Google's Core Web Vitals metrics. High CLS scores hurt both user experience and search rankings.
Lazy loading tells the browser to defer loading an image until it is about to enter the viewport. For images below the fold, this is a significant performance improvement. But the first image on most pages is typically the hero banner or featured image, which is the Largest Contentful Paint (LCP) element. Lazy-loading the LCP image delays the browser from loading the most important visible content, which directly increases the LCP time and hurts Core Web Vitals scores.
Search engines use image filenames as one of several signals to understand what an image depicts. Camera-generated filenames like IMG_1234.jpg, DSC_0032.jpg, or Screenshot_2024.png provide zero descriptive context. A filename like red-running-shoes-side-view.webp tells both the search engine and the URL structure something meaningful about the image. Filenames also cannot be changed after upload without breaking URLs and losing any accumulated link value.
No. The entire check runs in your browser using the built-in DOMParser API. Your HTML is never sent to any server. You can disconnect from the internet after the page loads and the checker still works.
No. Checking actual file sizes requires fetching each image URL from a server, which is a network request that browsers block for external URLs due to CORS restrictions. This tool works from HTML alone, which means it can audit the markup attributes but not the files themselves. To check file sizes, use browser DevTools, Google PageSpeed Insights, or WebPageTest.
Image Compressor
Reduce image file sizes by up to 90% for faster page load and better LCP scores.
PNG to WebP
Convert PNG images to WebP for 25 to 35 percent smaller files.
JPG to AVIF
Convert JPEG to AVIF for up to 50 percent smaller files at equivalent quality.
JPG to WebP
Convert JPEG to WebP for better compression and faster delivery.
Resize Image
Resize images to match their display dimensions and avoid loading oversized files.
Image Metadata Viewer
View EXIF data, GPS location and camera metadata. Strip it before publishing.
