Why compress an image?
A phone photo easily weighs 3 to 8 MB and is more than 4,000 pixels wide. That is far more than a website, an email or an online form needs: pages load slowly, emails bounce for being too big and many platforms reject files over 1 or 2 MB.
Compressing an image means saving it again with less data, so it weighs less and still looks good. This tool lets you control the three things that matter most: the compression quality, set with a 1 to 100 slider; the size in pixels, reduced by percentage or by setting a width and height; and the output format, which can stay the same or become JPG, PNG, WebP or AVIF.
Everything happens in your browser. Images are never uploaded to a server, so you can compress personal photos or scanned documents safely. Saving them again also removes EXIF metadata, which can include the camera model or the place where the photo was taken.
After processing you see the size before and after for each image, the percentage saved and a slider that compares the original with the result, so you can lower the quality until the difference is no longer visible. With ToolStudio Pro you can process several images at once and download them all in a ZIP.
How to compress an image
- Drag one or more images into the tool or click to choose them.
- Pick the output format: same as the original, JPG, PNG, WebP or AVIF.
- Set the quality with the slider or one of the quick presets.
- To change the size, choose a percentage or type the width and height in pixels.
- Click “Compress images”, compare before and after, and download the result (with Pro, every image in a ZIP).
When to use this tool
- Make the photos on a website or online shop lighter so pages load faster.
- Email photos without going over the attachment size limit.
- Upload an image to a form, portal or platform that only accepts small files.
- Resize photos to a set width, such as 1920 or 1080 pixels, for social media or slides.
- Compress PNG screenshots while keeping transparency.
- Convert photos to WebP or AVIF to publish them on the web with a smaller size.
Which quality should I choose?
- 70 to 85: the usual range for the web. The difference from the original is hard to see and the savings are usually large.
- 50 to 65: for thumbnails, previews or when file size matters more than detail.
- 88 to 95: for photos you will print or edit later.
- 100 for PNG saves without loss. Below 100, the tool reduces the number of colours in the image, as TinyPNG and other PNG compressors do.
Resize without distorting the image
With “Keep aspect ratio” on, the image fits within the width and height you enter without being distorted. If you only type one of the two values, the other is calculated for you. “Do not enlarge” stops small images from being scaled up and losing sharpness.
Formats
- Input: JPG, PNG, WebP, AVIF, GIF, BMP, SVG and ICO, plus HEIC when your browser can open it (Safari, for example).
- Output: JPG, PNG, WebP and AVIF. WebP and AVIF depend on your browser: Chrome, Edge and Firefox create both; if one is not available, the tool tells you.
Frequently Asked Questions
Are my images uploaded to a server?
No. Compression and resizing happen in your browser. Your images never leave your device.
How much smaller will my image be?
It depends on the image and the settings. A phone photo in JPG usually ends up at a fraction of its original size at quality 75, and much less if you also reduce its pixel size. The tool shows the size before and after for each image so you can check.
Can I choose the output quality?
Yes. A 1 to 100 slider sets the compression quality, and there are quick presets for smallest file, balanced, high quality and maximum. You can change it and apply again to compare.
How is a PNG compressed?
PNG is a lossless format, so at quality 100 it is saved as is. Below 100, the tool reduces the image to a palette of up to 256 colours with dithering, which is what makes a PNG much smaller. Transparency is kept.
Can I change the image format while compressing?
Yes. Keep the original format or save as JPG, PNG, WebP or AVIF. If you convert an image with transparency to JPG, transparent areas become white, because JPG does not support transparency.
What if the result is larger than the original?
This can happen with images that were already well optimised. With “If the result is larger, keep the original” on, the tool gives you back the original file in those cases, as long as you did not change the format or the size.
Can I compress several images at once?
Yes, with ToolStudio Pro. Add as many as you like; they are processed with the same settings and you can download them one by one or together in a ZIP. The free try covers one image.
Can I use the tool for free?
Yes. You can try it for free with one image and adjust the quality, size and format as often as you need. For unlimited use and several images at once, ToolStudio Pro costs €1.99 a month and includes every tool.