Guide
How to compress an image
- Choose an image. Select Choose Image or drop a JPG, PNG or WebP file onto the page. The image is opened by your browser and is not uploaded.
- Check the result. The image is compressed straight away with High Quality (Recommended). The panel shows the original and compressed file size, the width and height of both, the percentage saved and the exact setting used.
- Compare. Drag across the preview to compare the original (left) with the compressed version (right). Choose 100% to look at fine detail at actual size.
- Adjust if you want to. Move the slider toward Smaller File Size for a smaller file, switch to Lossless, or enter a Target size. You can also change the output format or resize the image.
- Download. Select Download to save the compressed copy. Your original file stays exactly as it was.
The compression levels, explained
| Level | What it does | Best for |
|---|
| Maximum Quality | JPEG or WebP quality 95, or lossless PNG. | Images where every detail matters, such as product photos or artwork. |
| High Quality (Recommended) | Smart mode: tries several settings, measures how closely each one matches the original, and keeps the smallest file that still matches very closely. Never goes below quality 82, or 90 for text and graphics. PNGs are compressed losslessly. | Almost everything. This is the default. |
| Balanced | JPEG or WebP quality 80 (88 for text and graphics while protection is on). PNGs are reduced to at most 256 colours. | Website images and email attachments where size matters more. |
| Smaller File Size | JPEG or WebP quality 70 (82 for text and graphics while protection is on). PNGs are reduced to at most 128 colours. | Thumbnails, previews and uploads with strict size limits. |
The Quality check line compares the compressed image with the original using SSIM (structural similarity), a standard way to measure how similar two images look, and focuses on the detailed parts of the picture where compression shows first. It is a guide, not a guarantee, so always look at the preview for images that matter.
High Quality is recommended when preserving the original appearance is important. Stronger compression can reduce file size further but may affect image quality.
Lossy and lossless compression
Lossy compression (JPEG and WebP quality levels) makes much smaller files by simplifying detail that is hard to see. Each step down in quality removes a little more. Lossless compression stores the picture more efficiently without changing any pixel, so the savings are smaller. When you choose Lossless, the tool decodes the result and checks it against the original pixel by pixel before showing it to you.
- PNG is always lossless at Maximum and High Quality. If an image has 256 colours or fewer, it is stored as an exact palette, which is often much smaller and still lossless.
- WebP can be lossless when your browser’s encoder supports it; the tool tests this for each image.
- JPEG can’t be saved losslessly, because every JPEG save changes some pixels. That’s why every setting starts again from your original file instead of re-compressing a compressed copy.
Text, screenshots and logos
JPEG-style compression can blur sharp edges and add faint blotches around text. With Protect text, graphics and screenshots switched on (the default), the tool checks whether your image looks like a screenshot, text or a logo. If it does, it uses higher quality settings and a stricter similarity check. For this kind of image, PNG or WebP usually gives a sharper result than JPEG.
Transparency
PNG and WebP images with transparent areas keep their transparency. The tool never converts a transparent image to JPEG on its own. If you choose JPEG yourself, it warns you first, because JPEG can’t store transparency and transparent areas become white.
Target file size
Some websites and forms only accept images under a certain size. In Target size mode, enter the size you need and the lowest quality you are willing to accept. The tool finds the highest quality that fits. If the target can’t be reached without going below your lowest quality, it shows the closest result and tells you so. It never lowers the quality further or resizes the image without asking. To reach a smaller size, you can allow a lower quality, resize the image, or try WebP.
Resizing
Images are never resized automatically. If you switch on Resize the image, you can set a new width and height (with or without keeping the aspect ratio) or pick 75%, 50% or 25%. The panel always shows the change, for example Original 4000 × 3000 px → New 2000 × 1500 px. Making a photo smaller in pixels is often the most effective way to reduce its file size, for example when a camera photo will only be shown on a website. Enlarging isn’t offered, because it can’t add real detail.
What happens to your images
Everything happens in your browser. The image is read from your device, compressed with your browser’s built-in image encoders and the tool’s own PNG optimizer, and saved through your browser’s normal download. Your images are not uploaded to our server, and we never receive, see or store them. Closing or refreshing the page clears them from memory.
Compressed files don’t keep the original’s metadata, such as camera details, the date taken or GPS location (EXIF). That makes them safer to share. The picture is turned the right way up first, so photos that relied on an orientation tag still display correctly. Colours are saved in sRGB, the standard colour space for the web.
Image Compressor FAQs
Will compressing reduce the quality of my image?
Lossy compression always changes the image slightly, but at the default High Quality level the changes are kept very small, and the tool measures them for you. If you need an exact copy, use Lossless mode with PNG or WebP.
Why is my compressed file not smaller?
Some images are already well compressed, for example a JPEG that was saved at a low quality before. Re-saving it at a high quality can even make it larger. The tool tells you when this happens and recommends keeping your original.
Which format should I choose?
Keep the original format unless you have a reason to change it. JPEG suits photos without transparency. PNG suits logos, screenshots and images with transparency. WebP works well for both and is supported by all current browsers, but some older software can’t open it.
Does the tool resize my image?
No, not unless you switch on Resize the image. The width and height of both versions are always shown in the result panel.
Can I compress the same image twice for a smaller file?
There’s no need. Every change of setting starts again from your original file, so quality is never lost by compressing an already-compressed copy. To get a smaller file, choose a stronger level instead.
Is there a size limit?
Files up to 60 MB and images up to 50 megapixels are accepted. Very large images use a lot of memory and may be slow on phones.
Are animated images supported?
No. If an animated PNG or WebP is added, only the first frame is kept, and the tool warns you.
Is the Image Compressor free?
Yes, completely free with no account, no watermark and no limit on the number of images.
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