Quick answer
- Resize first. Do not upload a 4000 px photo if it is shown at 1200 px.
- Pick the right format. WebP or JPG for photos, WebP or PNG for graphics.
- Set quality to 75–85%. This keeps photos looking the same.
- Compress with a browser tool like Zee Compressor, free and private.
What image compression does
Every picture is a grid of pixels, and each pixel stores colour information. Compression is a way of storing that information in fewer bytes, so the file is smaller, loads faster and is easier to send. There are two kinds:
- Lossy compression (JPG, lossy WebP) throws away tiny details that the human eye hardly notices. The file becomes much smaller, but the data that was removed cannot be brought back.
- Lossless compression (PNG, lossless WebP) rearranges the data without removing anything. The picture stays identical, but the saving is smaller.
For photos, lossy compression at a sensible quality is almost always the best choice. The trick is to stop before the damage becomes visible, and that point is usually higher than people expect.
Smaller images matter for websites too. Large pictures are one of the most common reasons a page loads slowly, and Google recommends that the main content of a page should appear within 2.5 seconds. Lighter images help you get there.
JPG vs PNG vs WebP: which format should you use?
Choosing the right format often saves more space than any quality slider.
| Format | Best for | Transparency | File size |
|---|---|---|---|
| JPG | Photos and detailed pictures | No | Small for photos |
| PNG | Logos, icons, screenshots, text | Yes | Large for photos |
| WebP | Almost everything on the web | Yes | Usually the smallest |
If you only remember one thing: use WebP for websites, JPG when you need a file that works everywhere, and PNG only when you need sharp edges on graphics. Need to change formats? Use our Image Converter.
How to compress images with Zee Compressor
Zee Compressor runs inside your browser. Your pictures are processed on your own device and are never uploaded to a server.
- Open the tool. Go to the Image Compressor.
- Add your images. Drag and drop one or many JPG, PNG or WebP files, or click Select Images.
- Choose the quality. Start at 80%. Move the slider left for a smaller file, or right for better quality.
- Choose the output format. Pick JPG or WebP. For a PNG with a transparent background, choose WebP so the transparency is kept.
- Click Compress Images. You will see the original size, the new size and the percentage saved for every picture.
- Download. Save each compressed image. Compare it with the original before you replace anything.
Best quality settings and file sizes
There is no single perfect number, because every picture is different. Use these values as a starting point and always look at the result.
| Use | Quality | Width | Target size |
|---|---|---|---|
| Website banner or hero photo | 75–80% | 1920 px | 100–250 KB |
| Blog or article photo | 70–80% | 1200 px | 50–150 KB |
| Online shop product photo | 80–85% | 1200–1600 px | 80–200 KB |
| Thumbnail | 70% | 400 px | Under 30 KB |
| Sharing by email or chat | 70–75% | 1600 px | 200–500 KB |
These are rules of thumb, not guarantees. A photo with lots of fine detail (leaves, hair, crowds) will be larger than a simple picture at the same quality.
Resize first, then compress
The number of pixels has a bigger effect on file size than the quality slider. A phone photo is often 4000 pixels wide, but a blog column is rarely wider than 1200 pixels. If you shrink the picture to the size it is actually shown at, you can cut the file size by more than half before compression even starts, and without any visible loss.
Use the Image Resizer to set an exact width and height, or the Image Cropper to remove parts of the picture you do not need. Then run the result through the compressor. If you have many files, the Bulk Compressor saves a lot of time.
Common mistakes to avoid
- Compressing the same file again and again. Each lossy save removes a little more detail. Always compress from the original.
- Saving photos as PNG. PNG files of photos are huge. Use JPG or WebP instead.
- Using JPG for transparent graphics. JPG has no transparency, so the background turns solid. Use WebP or PNG.
- Going too low on quality. Below about 50% you will see blocky patches and blurry edges, especially around text.
- Uploading full-size phone photos. Resize them first.
- Deleting the original. Keep an untouched copy so you can export it again in another size later.
Frequently asked questions
Does compressing an image reduce its quality?
It can, but it does not have to be visible. Lossy compression (JPG and lossy WebP) removes small details the eye barely notices, so at a quality of 70 to 85 percent most photos look the same while the file becomes much smaller. Lossless compression keeps every pixel but saves less space.
What is the best quality setting for compressing images?
For photos on a website, 75 to 85 percent is a good starting point. Go lower only if you need a very small file and are happy to check the result. Below about 50 percent, blocky patches and blurry edges become easy to spot.
Which is better for a website, JPG or WebP?
WebP is usually the better choice because it often creates files that are noticeably smaller than JPG at a similar look, and it supports transparency. All modern browsers can show WebP. Use JPG when you need maximum compatibility with older software.
Is it safe to compress images online?
It depends on the tool. Many sites upload your pictures to their server. Zee Compressor works inside your browser, so your images are processed on your own device and are not sent to us.
How can I reduce an image to about 100 KB?
First resize the image to the size you really need, because a smaller width means far fewer pixels. Then compress it and lower the quality slider step by step (for example 80, 70, 60) until the file size is where you want it. Check the result after each step.
Can I compress many images at once?
Yes. You can select several images together in the Image Compressor, or use the Bulk Compressor when you have a large batch.
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