File size vs dimensions — know what you need
Making an image 'smaller' can mean two different things. Reducing file size (measured in KB or MB) makes the file take up less storage and transfer faster over the internet. Reducing dimensions (measured in pixels) makes the image physically smaller on screen.
Often you need both. A 4000×3000 photo at 8 MB needs to become an 800×600 image at 150 KB for a website thumbnail. That's a dimension reduction and a compression step.
If you're hitting an upload limit stated in kilobytes, you need file size reduction — use the Compress Image to KB tool. If the image displays too large on your page, you need dimension reduction — use the Image Resizer. If both apply, resize first then compress.
Compress to reduce file size
The Image Compressor is the fastest way to shrink file size. Drop your image, adjust the quality slider, and watch the output size update in real time. Download when you're happy with the balance of size and quality.
For photos, 75–85% quality is the sweet spot — the file shrinks dramatically and the difference is invisible at normal viewing sizes. For images with text or sharp edges, use 85–90% or consider converting to PNG.
All compression runs in your browser. Your image is never uploaded anywhere. This is the same Canvas API compression that desktop tools use, just without the desktop.
Resize to reduce dimensions
The Image Resizer lets you set exact pixel dimensions or scale by percentage. Lock the aspect ratio to avoid stretching — a 4000×3000 photo resized to 1000px wide becomes 1000×750 automatically.
Resize to the largest size the image will actually be displayed. There's no benefit to uploading a 3000px-wide photo to a blog that renders images at 800px. You're loading pixels nobody sees.
For profile photos, passport photos, and social media images, check the platform's recommended dimensions and resize to match before uploading.
Convert format for additional savings
Format conversion can shrink files beyond what compression alone achieves. Converting JPG to WebP typically saves 25–35% at the same visual quality. Converting PNG to JPG (when transparency isn't needed) can reduce file size by 80% or more.
The Image Converter handles format changes for individual files or batches. Convert first, then compress the output for maximum size reduction.
For strict KB limits on upload forms, the Compress Image to KB tool targets an exact file size — it adjusts quality and dimensions automatically until the output fits your limit.
A simple workflow without Photoshop
For email attachments: compress at 80% quality. If still too large, resize to 1920px on the longest side, then compress again.
For website images: resize to display dimensions, convert to WebP, compress at 80%. Three steps, all in the browser, under a minute per image.
For upload forms with KB limits: crop to the required framing, resize to minimum required dimensions, then use the KB compressor to hit the exact limit.
For social media: crop to the platform's aspect ratio, resize to recommended pixel dimensions, compress if the platform has a file size cap.