Free Image Size Checker

Check the dimensions, file size, format and aspect ratio of any image — and get a straight answer on whether it is too heavy for a web page.

Runs entirely in your browser — nothing is uploaded

Drop images here, or choose filesUp to 20 images at once. JPEG, PNG, WebP, GIF, AVIF or SVG, up to 25 MB each.

Your images stay on your device. Every one of these image tools runs entirely in your browser — nothing is uploaded, nothing is stored, and there is no server involved. You can check for yourself: disconnect from the internet after this page loads and the tool still works.

This reads the file itself. How the image performs on a real page also depends on whether it is lazy-loaded, whether responsive sizes are served, and how it is cached — none of which can be seen from the file alone.

What this tool does not do: Reads the file itself. How an image actually performs on a page also depends on lazy loading, responsive sizes and caching, which cannot be seen from the file.

How to use this tool

Drop one or more images onto the page, or choose files.
Read the dimensions and file size.
Act on the notes — anything over 200 KB is usually worth compressing.

What is Image Size Checker?

Oversized images are the most common cause of a slow page, and the easiest to fix. A photo straight from a phone is often 4 MB and 4000 pixels wide, displayed in a slot 800 pixels across. The visitor downloads all of it.

Two numbers matter and they are frequently confused. Dimensions are how many pixels the image contains; file size is how many bytes travel over the network. Reducing dimensions usually reduces file size, but a 500-pixel image saved badly can still weigh a megabyte.

Best practices

Keep content images under 200 KB where you can; hero images under 400 KB.
Serve images no larger than they display, allowing 2x for high-density screens.
Use WebP or AVIF for photographs, SVG for logos and icons.
Always set width and height in the HTML so the page does not jump as images load.
Add loading="lazy" to images below the fold.

Frequently asked questions

Do image sizes affect SEO?

Indirectly but genuinely. Heavy images slow a page down, and page experience is a ranking factor — a small one, but a real one. The larger effect is on people: slow pages get abandoned before they finish loading.

What size should images be?

It depends on where they appear. A full-width hero on a 1440px layout wants around 1920px wide to stay sharp on high-density screens. A blog image in a 700px column wants around 1400px. A thumbnail wants a few hundred. Serving more than that is wasted bandwidth.

Is my image uploaded anywhere?

No. It is read by your own browser and never sent anywhere. There is no upload endpoint in this tool. Disconnect from the internet after the page loads and it will still work.