Compress Images for Faster Web Pages (Core Web Vitals)

Most slow pages are not slow because of a weak server. They are slow because a 4000-pixel camera photo is sitting in a 360-pixel column. The browser still downloads every extra pixel. Largest Contentful Paint (LCP) is usually that hero image. If it is 3 MB, first-time visitors on mobile data wait, bounce, and never see the text underneath.

Compression keeps the same width and height while storing the pixels more cheaply. That is different from resizing, which actually removes pixels. The winning order for a website is: resize to the display size (with 2x for retina if you need it), then compress. Doing only compression on a 12-megapixel photo still leaves a heavy file.

What to aim at

• Hero / LCP image: often 80-200 KB after resize + compress. If it is still over 500 KB, the dimensions are probably still too large.
• Inline photos: 30-120 KB is typical for a blog figure.
• Thumbnails: a few tens of KB. They should never be the original camera file.
• PNG logos: compress, but do not expect JPEG-like savings. If the logo is a photo, convert to JPG or WebP first.

Need an exact form cap such as 100 KB? Use Compress Image to KB. For page speed, quality-based compression after a resize is usually enough.

How to compress for the web

1. Resize to roughly twice the CSS width. A 600 px column wants about 1200 px wide, not 4000. Use the Image Resizer.
2. Run Image Compressor. It stays in your browser. JPG, PNG and WebP stay in the same format. You should see a large drop on photos, often around 80%+.
3. Check the result at 100% on a phone-sized screen. If you cannot tell, you went far enough. If type or edges smear, ease the quality back one step.
4. Re-test the page with the Website Speed Test. One image change at a time tells you what actually moved LCP.

Everything in the compressor runs on your device. Product shots and unpublished screenshots never leave the computer.

Mistakes that keep pages heavy

• Compressing a full-resolution original and calling it done.
• Saving a screenshot full of text as a heavy JPG. PNG or WebP may look cleaner for UI captures.
• Uploading the same 2 MB image into every blog post "because it looks sharp on a 5K monitor".
• Chasing a perfect 100 speed score after the hero is already under 150 KB. Other issues are now cheaper to fix.

Frequently asked questions

Will compression ruin photo quality?

A sensible pass on a photo is usually invisible on the web. You will notice it first on fine hair, gradients and small text. Compare before and after at the size it will actually display.

Is this private?

Yes. Image Compressor runs in the browser. Nothing is uploaded.

Should I convert to WebP as well?

WebP is often smaller at similar quality. Convert after you have the right dimensions, using the JPG to WebP tool, and keep a JPG fallback if you still support very old browsers.

Open the Image Compressor and shrink the files that are actually in the page. Free, no signup.