Free Image SEO Checker
Enter a URL, or paste your HTML, and get an image SEO score out of 100 plus an image-by-image audit: missing alt text, heavy files, old formats, oversized dimensions, broken images, lazy loading, file names and your social share image.
- 20 checks, 6 categories
- Measures the real image files
- We don't store your pages or images
Checking images…
Image SEO score
Good
Score by category
Fix these first
Ranked by how many points each fix could add.
Heaviest images
The files adding the most weight to the page.
Every image on the page
Each image with its alt text, file facts and the issues found.
All checks
Select any check for why it matters and how to fix it.
Want an expert to fix it, or to learn how yourself?
A tool finds the issues; judgment decides which ones matter for your business. I offer hands-on SEO and technical audits for businesses in Nepal and worldwide, and teach SEO in my course.
How the score is calculated
Every page starts at zero and earns points across six categories worth 100 in total. Each check is fully passed, partly passed or failed, and every result explains why it matters and how to fix it.
| Category | What is checked | Points |
|---|---|---|
| Alt Text | Every image has an alt attribute; alt text is descriptive (not a file name, “image” or keyword-stuffed); linked images have alt text; alt text isn't copied across different images. | 25 |
| File Size & Weight | Each file's real size, the total weight of the images, pixel dimensions compared with display size, and browser caching. Needs the image files. | 22 |
| Formats | Share of images served as WebP or AVIF, and whether large PNGs, GIFs or non-web formats are used where a better format exists. Needs the image files. | 13 |
| Loading & Layout | Width and height attributes (no layout shift), lazy loading below the fold, an eager main image, and srcset for large images. | 14 |
| File Names & URLs | Descriptive file names instead of IMG_1234.jpg, and clean URLs: lowercase, hyphenated, no spaces or special characters. | 10 |
| Findability | No broken images, real image URLs in src or srcset (not only data-src), a valid og:image of a good size, and no http:// images on https:// pages. | 16 |
| Total | If a check can't apply (for example, file-size checks when the image files couldn't be fetched, or lazy-loading checks on a page with three images), it is left out and the score is scaled to the points that did apply. | 100 |
90-100
Excellent
75-89
Good
50-74
Needs work
0-49
Poor
Image SEO best practices in six rules
The checks follow the same checklist I use when auditing client sites. Get these right and your images load fast, work for every visitor and have a chance to appear in Google Images.
1. Describe every image
Write a short, natural alt text for each meaningful image. Leave alt empty only for pure decoration, and never stuff keywords.
2. Keep files light
Aim for under 200 KB per image and about 1 MB of images per page. Resize to the displayed size first, then compress.
3. Use modern formats
Serve WebP or AVIF for photos, SVG for logos and icons, and video instead of animated GIFs.
4. Reserve the space
Set width and height on every image so the page doesn't jump while loading, and offer several sizes with srcset.
5. Load the right images first
Lazy-load images below the first screen, but never the main image at the top: it should load immediately.
6. Name files clearly
Rename IMG_1234.jpg to something like kathmandu-seo-workshop.webp: lowercase words separated by hyphens.
What an image checker can't tell you
A high score means your images are set up well, not that they will rank. These things matter too, and no automated tool can judge them.
Relevance and quality
Whether an image fits the topic, looks professional and is original needs a human eye.
Real-world speed
Largest Contentful Paint comes from real visitors. Use PageSpeed Insights or Search Console for that.
JavaScript-added images
The tool reads the raw HTML. Images inserted by scripts need the Paste HTML tab with the rendered code.
Google Images rankings
Whether Google has indexed your images, and how they rank, is only visible in Search Console.
For the things this tool can't see, use Google's free tools: Search Console, PageSpeed Insights and Google's image SEO best practices.
What image SEO is and what an image SEO checker looks at
Image SEO means preparing the pictures on a page so that search engines can find and understand them and visitors do not wait for them. It covers the HTML around an image, such as the alt text, file name and width and height attributes, and the file itself: its format, its pixel size and its weight in kilobytes.
Google's image best practices put the basics in plain terms. Use an HTML img element, because Google does not index CSS images. Write useful alt text, which Google calls the most important image metadata. Give files short descriptive names, and use a supported format such as JPEG, PNG, WebP, AVIF or SVG. Images also decide how fast a page feels, because the largest element on screen is often a photo, and Largest Contentful Paint should be 2.5 seconds or less.
An image SEO checker applies those rules to a real page. It lists every image, fetches the files to measure their weight and format, flags missing alt text, lazy loading in the wrong place and broken files, and puts the heaviest images at the top of your fix list. It cannot judge whether a picture is relevant or well made, so a person still has to look.
When to run an image SEO check
Run it before a launch and any time a page feels slow or its pictures are missing from search.
When a page loads slowly
Open the heaviest images list first. One or two photos uploaded at full camera size often account for most of a page's weight, and resizing them is a quick win.
For online store catalogues
Check a product page and a category page. Product photos taken on a phone are often uploaded at full size, and a category page with many thumbnails multiplies the cost.
Before and after a launch
Run it on staging with the Paste HTML tab, then again on the live URL. A theme or CDN change can alter formats, lazy loading and file paths without warning.
In an accessibility review
Read each image's alt text as a screen reader user would. Empty alt for decoration, a clear description for meaningful images, and a purpose for linked images.
Before sharing a page
The social share image shows what people see on Facebook or WhatsApp. Check that it exists, loads and is large enough, so a link does not appear with a blank preview.
After adding a lazy-load plugin
Confirm that the real image URL is still in src or srcset, and that the main image at the top of the page is not delayed.
Image SEO mistakes and how to fix them
Most image problems come from uploading files untouched and trusting a plugin to sort them out.
Missing, copied or stuffed alt text
What goes wrong: Images with no alt attribute, the same phrase on every image, or a string of keywords give search engines and screen reader users no useful description.
The fix: Describe what the image shows in a short, natural phrase. Use alt="" for purely decorative images, and describe the purpose of an image that works as a link.
Content images set as CSS backgrounds
What goes wrong: Google does not index CSS images, so a product photo or diagram placed as a background will never be found in image search.
The fix: Use an img element for any image that carries meaning. Keep CSS backgrounds for decoration, such as patterns and textures.
Lazy-loading the main image
What goes wrong: Adding loading="lazy" to the large image at the top can delay it, which hurts Largest Contentful Paint. Google also advises against lazy-loading content that is visible immediately.
The fix: Lazy-load images below the first screen only. Leave the top image on normal loading so the browser fetches it straight away.
Lazy-load scripts that hide the real URL
What goes wrong: Some scripts store the image address only in data-src and fill src after a scroll or click. Google does not scroll or click, so those images can be missed.
The fix: Use the browser's built-in loading="lazy" with a real src, or an IntersectionObserver setup that needs no user action, and confirm it with the URL Inspection tool.
Huge originals and no dimensions
What goes wrong: A 4000 pixel photo shown in an 800 pixel slot wastes bytes, and an image with no width and height lets the page jump as it loads, which raises layout shift.
The fix: Resize to the largest size actually displayed, then compress. Add width and height, and offer several sizes with srcset plus a fallback src.
Camera file names and generic names
What goes wrong: Names such as IMG_4821.JPG or image1.jpg say nothing about the picture, and Google's guidance recommends short, descriptive file names.
The fix: Rename before upload, for example red-trail-running-shoes.webp. Use lowercase words separated by hyphens, and translate or URL-encode names that use non-Latin characters.
Image SEO terms explained
- Alt text
- The
altattribute of an image. It is read by screen readers, shown when an image fails to load, and used by Google to understand the image. An emptyaltmarks the image as decorative. - Lazy loading
- Delaying an image download until it is near the screen. The browser supports it through
loading="lazy". Used on images below the first screen, it saves data without hiding them from search. srcset- An
imgattribute that lists several sizes of the same image, so the browser can pick the best fit for the screen. Google asks for a fallbacksrcURL as well. - WebP and AVIF
- Modern image formats that usually give smaller files than JPEG or PNG. A Google study of WebP reported lossy files 25 to 34 percent smaller than JPEG at the same SSIM quality score.
- Largest Contentful Paint (LCP)
- A Core Web Vital that times when the largest visible element, often an image, finishes drawing. Google's guideline for a good result is 2.5 seconds or less.
- Layout shift
- Movement of content as a page loads. Giving images
widthandheight, or reserving space with CSSaspect-ratio, lets the browser set aside room before the file arrives. og:image- An Open Graph tag naming the image for link previews. Google can also use it, along with schema.org markup, when choosing the image to show for a page.
- Image sitemap
- A sitemap extension that lists images Google might not otherwise find. It can point to images hosted on another domain, such as a CDN.
Related tools, guides and services
Finding heavy images is the first step. These help you fix them and measure the effect.
Image Compressor
Shrink JPG, PNG and WebP files in your browser and compare before and after.
ToolCore Web Vitals Checker
Check LCP, INP and CLS to see whether lighter images improved the page.
ToolOn-Page SEO Checker
Score the rest of the page, including alt text, headings, links and tags.
GuideSEO for Nepali ecommerce
See how product photos, alt text and page speed fit into a full store SEO plan.
GuideSEO audit errors that matter
Learn why missing alt text matters for some images and not for decorative ones.
ServiceTechnical SEO service
Get image delivery, caching and page speed reviewed across your whole site.
Built by
Madhav Kushwaha
SEO, AEO, GEO & Digital Marketing Consultant in Kathmandu, Nepal, and trainer at ODcrU Academy and TechAxis Institute. I built this checker because images are the most common reason pages I audit are slow, and the easiest thing to fix. The scoring above is exactly what the code does.
Image SEO Checker: Frequently Asked Questions
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