Image Tools · · 4 min read
How to Compress Images Without Losing Visible Quality
Shrink image files for faster sites and smaller emails: the right format, quality and size to use, plus a free compressor that never uploads your photos.
To compress an image without a visible drop in quality, do two things: resize it to the largest size it will actually be shown at, and re-save it as WebP or JPG at around 70–80% quality. The Toolbench Compress Image tool does both in one step — it defaults to WebP, 70% quality and a 1,920-pixel maximum width — and it runs entirely on your device, so your photos are never uploaded.
This guide explains where the file size actually comes from, which settings to use for common jobs, and how to check you haven't gone too far.
Why image size matters
Images are usually the heaviest part of a web page. Oversized photos slow page loads, which hurts both visitors on mobile data and search performance — page speed is one of the signals search engines consider. Smaller images also mean emails that don't bounce off attachment limits and uploads that finish faster.
Where the file size comes from
Two things drive most of an image's size:
- Pixel dimensions. A 4,000 × 3,000 photo straight from a phone has 12 million pixels. Shown in a 1,200-pixel-wide blog column, three-quarters of those pixels are wasted. Halving the width cuts the pixel count — and usually the file size — by about 75%.
- Format and quality. Lossy formats (JPG, WebP) throw away detail the eye barely notices. Quality around 70–80% often halves the file again with no visible difference at normal viewing size.
Resizing is the bigger win for camera photos; quality is the bigger win for images that are already the right size.
How to compress an image with Toolbench
- Open Compress Image.
- Drop an image onto the tool, paste one from your clipboard, or click to choose a file.
- Adjust Quality (it starts at 70%).
- Choose the output format: WebP or JPG.
- Set Max width — 1,920 px by default. Wider images are scaled down proportionally; set it to 0 to keep the original dimensions.
- Check the result line, which shows the new dimensions, format, file size and how much smaller it is than the original. Then download it, or sign in and save it to your Gallery.
Which settings to use
| Job | Format | Quality | Max width |
|---|---|---|---|
| Blog or article photo | WebP | 70–80% | 1,600–1,920 px |
| Full-width hero image | WebP | 75–80% | 2,000–2,400 px |
| Product photo | WebP or JPG | 80–85% | 1,200–1,600 px |
| Email attachment | JPG | 70% | 1,280–1,600 px |
| Thumbnail | WebP | 60–70% | 400–600 px |
Why WebP? At the same visual quality, WebP files are usually noticeably smaller than JPGs, and every modern browser supports them. Use JPG when you need maximum compatibility — some email clients and older software still don't handle WebP.
Transparency, screenshots and graphics
- Transparent images: WebP keeps transparency. JPG doesn't support it, so transparent areas are filled with white.
- Screenshots, logos and text-heavy graphics: lossy compression can blur sharp edges and text. Keep the quality higher (85%+) or convert them to PNG with the Convert Image Format tool instead.
Check before you publish
Compression is a judgement call, so take ten seconds to check:
- View it at 100%, especially faces, skin and gradients like skies — that's where artefacts (blockiness or banding) show up first.
- Compare against the original at the size it will actually be displayed.
- Don't re-compress a compressed file repeatedly. Each lossy save loses a little more detail. Always start from the original.
Privacy bonus: metadata is removed
Photos from phones often carry hidden EXIF metadata — camera model, date and sometimes GPS location. Because the compressor re-draws the image and saves a fresh file, that metadata isn't carried over, which is a good thing for anything you post publicly.
Related image tools
- Resize Image — exact pixel dimensions without other changes.
- Crop Image — trim to 1:1, 16:9, 4:5 and other ratios.
- Social Media Resizer — exact sizes for Open Graph, Instagram, X, LinkedIn and YouTube.
- Convert Image Format — switch between PNG, JPG and WebP.
Frequently asked questions
Are my images uploaded when I compress them?
No. They're decoded and re-encoded by your browser on your own device. Only if you sign in and choose to save a result to your Gallery is that copy stored — privately — in your account.
What quality setting is best?
Start at 70–80%. For most photos the difference from 100% is invisible at normal size while the file is dramatically smaller. Go higher for images with text or fine detail.
Should I use WebP or JPG?
WebP for websites — it's usually smaller at the same quality and supported by all modern browsers. JPG when the image is going somewhere that may not support WebP, like some email clients or older software.
Why is my compressed image bigger than the original?
It can happen when the original was already heavily compressed, or when you raise the quality above the original's. Lower the quality or keep the original.
Does compressing an image remove its location data?
Yes. The tool saves a fresh file from the pixels alone, so EXIF metadata such as camera details and GPS coordinates isn't included in the result.
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