How to Compress Images Without Losing Quality (2026 Guide)
Big images are the number one reason websites load slowly, emails bounce and online forms reject your upload. The good news is that most photos can be made 50–90% smaller with no difference you can see. This guide explains exactly how, whether you are optimising a website, sending photos or filling in an application form.
Why image files are so large
A modern phone camera captures 12–50 megapixels and saves photos at very high quality, often 3–8 MB each. That detail is useful for printing a poster, but a website or email shows the same photo at a fraction of that size. You are sending millions of pixels and fine compression detail that nobody will ever see.
Two things control file size:
- Dimensions: the number of pixels (for example 4000 × 3000).
- Compression: how efficiently those pixels are stored, which depends on the format and quality setting.
Getting both right is the secret to small, sharp images.
Step 1: Resize to the size you actually need
Resizing gives the biggest saving of all. Halving the width and height leaves only a quarter of the pixels. Typical sizes that are more than enough:
- Full-width website banner: 1920 px wide
- Blog or product image: 1200 px wide
- Email image: 600–1200 px wide
- Social media post: 1080 px wide
Use our free image resizer to set an exact width, or scale by percentage. Keep the aspect ratio locked so nothing looks stretched.
Step 2: Choose the right format
- JPG: best for photos. Excellent compression, universal support, no transparency.
- PNG: best for logos, icons and screenshots with sharp text. Lossless, supports transparency, but files are large.
- WebP: best for websites. Usually 25–35% smaller than JPG at the same quality, supports transparency and works in all modern browsers.
A common mistake is saving photos as PNG. A photo saved as PNG can easily be five times bigger than the same photo as a JPG or WebP. If you have one, convert it with PNG to JPG or PNG to WebP.
Step 3: Use the right quality setting
JPG and WebP use lossy compression. They throw away detail the eye is not sensitive to, and the quality setting controls how much. Cameras save at 95–100%, but you can go much lower before any change is visible:
| Quality | Typical saving | Visible difference |
|---|---|---|
| 90% | 40–60% | None |
| 80% | 60–75% | None for almost all photos |
| 70% | 70–85% | Very slight, only when zoomed in |
| 50% | 80–90% | Noticeable on smooth gradients and text |
For most websites, 75–80% is the sweet spot. For photos with fine text or product detail, stay at 85–90%.
Step 4: Compress, and check the result
Open the ToolMaxo image compressor, drop in your images and leave the format on Auto. It tries your original format and WebP, keeps the smaller one and shows you the saving for each file. Everything runs in your browser, so your photos are never uploaded.
Always compare the result with the original at 100% zoom on the part of the image that matters most, such as a face, a product label or text. If you see blocky areas or blurry edges, raise the quality a little.
Compressing to an exact size (20 KB, 50 KB, 100 KB)
Many online forms, especially exam, job and government portals, set a strict upload limit. Instead of guessing quality settings, type the limit into the compressor’s Target file size field. It finds the highest quality that fits automatically. There are shortcuts for the most common limits: 20 KB, 50 KB, 100 KB and 200 KB.
Image compression and SEO
Google measures real-world page speed through Core Web Vitals. The most important one for images is Largest Contentful Paint (LCP), the time it takes for the biggest element, often a hero image, to appear. Heavy images are the most common cause of a poor LCP score. Compressing and resizing images is usually the fastest single fix for a slow site.
While you are optimising, also:
- Give files descriptive names, such as
heathrow-airport-taxi.webpinstead ofIMG_4821.jpg. - Add useful alt text that describes the image for screen readers and Google Images.
- Set width and height attributes so the page does not jump while images load.
- Lazy-load images that are below the fold (WordPress does this automatically).
Common mistakes to avoid
- Compressing the same JPG again and again. Each save loses a little more quality. Always compress from the original.
- Uploading 4000 px photos to a website and relying on the browser to shrink them.
- Using PNG for photos. Use JPG or WebP instead.
- Going too low on quality for images with text, logos or faces.
- Forgetting mobile. Most visitors are on phones with slower connections.
Quick checklist
- Resize to the display size.
- Use JPG or WebP for photos, PNG or WebP for graphics.
- Compress at 75–85% quality.
- Check the result at 100% zoom.
- Name the file well and add alt text.
Follow these five steps and your images will typically end up 70–90% smaller, your pages will load faster, and nobody will notice any loss in quality.
