Image Optimizer

This image optimizer compresses, resizes, and converts your images to WebP in one step, so they load fast without looking worse. Use it to compress images, resize images, and convert to WebP in a single pass. Drop in one photo or a whole batch, and you get smaller files with search-friendly names, the exact dimensions your site needs, and optional responsive sizes with ready-to-paste HTML. Everything happens in your browser: your images are never uploaded.

Why image optimization matters for SEO

Images are usually the heaviest part of a web page, and on many pages the largest image is also the Largest Contentful Paint (LCP) element, one of Google’s Core Web Vitals. A 4 MB photo straight from a phone can take seconds to load on mobile data, while the same photo resized and saved as WebP often weighs around a tenth of that and looks the same on screen.

Faster images improve page experience, reduce bounce, and save bandwidth for your visitors and your hosting. Optimized images with descriptive file names and alt text are also easier for Google Images to understand and show.

Which image format should you use?

How big should your images be?

Resize images to the largest size they’ll actually be shown at, not the size your camera took. A 4032-pixel-wide phone photo shown in a 800-pixel-wide blog column wastes most of its weight. These widths cover most sites:

• Blog and content images: about 1200 pixels wide, which stays sharp on high-density screens at typical column widths.
• Full-width hero images: about 1920 pixels wide.
• Social share (Open Graph) images: 1200 × 630 pixels, the size Facebook, LinkedIn, and X display well.
• Thumbnails: 300 to 400 pixels, square or in the ratio your theme uses.

The presets in the Resize section set these for you. “Fit” keeps the original shape inside a maximum width and height, while “Exact size” crops from the center to fill the dimensions exactly, which suits social images and thumbnails.

How much should you compress?

When you compress images for the web as WebP or JPG, a quality between 75 and 85 is the sweet spot for most photos: files shrink dramatically and the difference is hard to see. Below about 60, you’ll start to notice blur and blocky edges, especially around text, faces, and sharp lines. Use Compare to check each image side by side at full size before you download it.

If your site or a platform has a size limit, tick Keep each image under a maximum file size. The tool lowers the quality step by step until each image fits, and tells you if an image can’t reach the limit without also reducing its dimensions.

Responsive images with srcset

A single large image is wasted on a phone. With responsive images, the browser picks the smallest file that still looks sharp on each screen. Turn on Responsive sizes and the image optimizer creates several widths of each image, plus HTML like this:

<img src="…" srcset="…-480w.webp 480w, …-800w.webp 800w, … 1600w" sizes="(max-width: 800px) 100vw, 800px" width="1600" height="1200" alt="…" loading="lazy">

The width and height attributes reserve space so the layout doesn’t jump while images load, which protects your Cumulative Layout Shift score. Keep loading="lazy" for images further down the page, but remove it from the main image at the top, which is often the LCP element; lazy-loading it slows down LCP. See web.dev’s guide to optimizing LCP for more.

If you use WordPress, you usually don’t need the srcset HTML: WordPress creates its own sizes and srcset when you upload an image. Upload one optimized image at the largest size your theme needs, and let WordPress handle the rest. WordPress has supported WebP uploads since version 5.8 and AVIF since 6.5.

File names and alt text

File names and alt text are the two easiest image SEO wins. Google’s image guidelines recommend short, descriptive file names. red-trail-running-shoes.webp tells search engines what the image shows; IMG_4021.JPG tells them nothing. Type a description in File names and the tool turns it into a clean, hyphenated name, numbering several images automatically. Without a new name, original names are still cleaned up: lowercase, no spaces, no special characters.

Alt text matters even more. It describes the image for people using screen readers and gives search engines context. Write what the image shows in a short sentence, without stuffing keywords. The srcset HTML includes an alt field for each image so you can add it before copying.

Metadata and privacy

Photos from phones and cameras often contain hidden EXIF metadata, including the exact GPS location where the photo was taken. Because every image is re-encoded, this image optimizer removes that metadata automatically, which protects your privacy and trims a few more kilobytes. Images are processed on your device and are never uploaded.

One trade-off to know: re-encoding also removes IPTC copyright and credit fields, which Google Images can use to show licensing details. If you rely on that metadata, add it back with your photo software or your digital asset management system after optimizing.

Watermarks: adding yes, removing no

You can add a text watermark, such as your brand name or a copyright notice, to protect images you own, in a corner, the center, or tiled across the image. This image optimizer doesn’t remove watermarks. A watermark usually marks someone else’s copyright, and removing it to use the image without a license can infringe that copyright; in the US it can also break laws that protect copyright information, such as Section 1202 of the DMCA. If you need an image without a watermark, license it from the owner or use a free stock photo site.

Image SEO is only part of page speed. Once your images are optimized, check the rest of your technical setup with the other technical SEO tools.