Check Image Dimensions on Any Website

Enter a URL to instantly check the dimensions of every image on the page — natural file size, rendered size, and visibility, all in one report.

How It Works

  1. Enter the full URL of any website (including https://)
  2. Our service will scan the page and render all JavaScript
  3. We'll analyze every image on the page, including background images
  4. View detailed information about each image's dimensions and properties
Natural Dimensions

See the original size of each image file

Rendered Size

Compare with how images appear on the page

Complete Analysis

Includes HTML and CSS background images

Enter a URL to analyze

Scan a whole page, paste a direct image link, or drag & drop / paste an image to check one image instantly.

Note: For best results, enter the complete URL including the protocol (https://).

This tool respects website robots.txt files and privacy policies. Some images may not be accessible due to CORS restrictions.

Image Optimization Guides

All guides →

References and walkthroughs for getting images right on the modern web.

Best Image Sizes for Websites

Recommended dimensions for hero, blog, thumbnail, OG, and favicon images.

Shopify Image Sizes

Product, collection, slideshow, and logo sizes for Shopify stores.

WordPress Featured Image Size

Featured image, default sizes, WebP support, and storage tips for WordPress.

Open Graph Image Size

Per-platform OG image dimensions, required tags, and testing tools.

Free Image Tools

All tools →

Browser-based converters and utilities — files never leave your device.

Website Image Size Checker

Scan any URL to audit every image on a page — dimensions, rendered size, type, and CSS backgrounds.

PNG to WebP Converter

Convert PNG to WebP in your browser. No upload, adjustable quality, batch support.

Research & Blog

Original data on how real websites handle images, plus practical, developer-focused writing.

State of Web Image Optimization 2026

We scanned 44 popular sites: 68% ship oversized images. Aggregate data, by segment.

Read the blog →

Right-sizing images, formats, Core Web Vitals, and auditing real sites.

Developer integrations: MCP server, CLI & GitHub Action →

Why Image Dimensions Matter

Every image on a page carries two different sizes: the natural dimensions of the file itself, and the rendered size it occupies once CSS and layout are applied. Browsers download the whole file regardless of how small it ends up on screen — so a 3000-pixel photograph placed in a 600-pixel column costs your visitor every one of those wasted pixels.

Because file size scales with area, the waste compounds fast: an image twice as wide as it needs to be is roughly four times the bytes. It is the most common reason a page feels slow, and it directly affects Largest Contentful Paint — one of the Core Web Vitals Google measures.

The fix is rarely dramatic. Serve images at about twice their rendered width to stay sharp on retina screens, use a modern format like WebP, and set width and height attributes so the browser can reserve space and avoid layout shift. Our own scan of 44 popular sites found 68% shipping oversized images — this is close to universal.

Start with the scanner above, then see the recommended image sizes reference or the guide to finding oversized images.

Checking images at scale?

Bulk-audit hundreds of URLs at once or hit a dimensions API from your own code.

Bulk & API →

Frequently Asked Questions

How do I check the image dimensions on a website?

Paste the page URL into the scanner above. It loads the page in a real browser, renders the JavaScript, and reports every image it finds — including CSS background images — with both the natural dimensions of the file and the size it actually renders at. You can also open your browser devtools and hover an image element, but that only shows one image at a time and misses background images.

What is the difference between natural and rendered image size?

Natural size is the real pixel dimensions of the image file, for example 3000×2000. Rendered size is the space it actually occupies on the page after CSS and layout are applied, for example 600×400. When natural size is far larger than rendered size, the visitor downloads far more data than the design needs — that gap is the single most common image performance problem on the web.

How do I find oversized images on my site?

Scan the page and compare each image's natural width against its rendered width. Anything more than roughly twice the rendered width is oversized, since 2× covers retina displays. Because file size scales with area, an image twice as wide as it needs to be is roughly four times the bytes it should be.

Do I need to install anything?

No. The scanner runs on our server and returns a report in your browser — nothing to install and no signup. The converter and metadata tools go one step further and run entirely in your browser, so those files never leave your device.

Does it work on any website?

It works on any publicly reachable page. Pages behind a login, on a private network, or actively blocking automated visitors cannot be scanned. A small number of images may report unavailable file sizes when the host blocks cross-origin requests, though their dimensions are still reported.

Is this image size checker free?

Yes — the scanner and every tool on the site are free, with no signup and no watermark.