How to Check Image Dimensions on a Website

Whether you're auditing performance, debugging layout issues, or optimizing for SEO, knowing the actual dimensions of images on a webpage is essential. Here are three methods, from manual to fully automated.

Method 1: Browser DevTools (Manual)

Every modern browser lets you inspect image dimensions directly:

Right-click the image and select Inspect (or press F12)
The Elements panel highlights the <img> tag
Hover over the image URL in the panel to see a tooltip showing:

Intrinsic size: 1920 × 1080 px
Rendered size:  480 × 270 px
Aspect ratio:   16:9
File size:      245 KB

Limitation: This only works one image at a time and misses CSS background images. For pages with 50+ images, this approach is slow.

Method 2: Right-Click → "Open Image in New Tab"

A quick way to see an image's natural dimensions:

Right-click the image
Select Open Image in New Tab
The browser tab title shows the dimensions (e.g., "photo.jpg (1920×1080)")

Limitation: Only shows natural dimensions, not rendered size. Doesn't work for CSS background images or images inside iframes.

Method 3: Automated Scan (Recommended)

For a complete picture, use an automated tool that scans the entire page at once. Our Image Dimensions Analyzer renders the full page in a headless browser, then reports every image — including CSS backgrounds and JavaScript-loaded images.

What you get with an automated scan:

Every image on the page in a single report
Natural AND rendered dimensions side by side
CSS background images (invisible to right-click)
JavaScript-rendered images (React, Vue, etc.)
Visibility status and image type classification

Skip the manual work — scan an entire page in seconds.

Scan a Website Now

Which Method Should You Use?

Method	Best For	Limitations
DevTools	Checking 1-2 specific images	Manual, misses CSS backgrounds
Open in New Tab	Quick natural size check	No rendered size, no CSS images
Automated Scan	Full page audits, performance reviews	Requires network request