Compress images without an obvious loss of quality
Choose the right format, dimensions and quality level for smaller images that still look clear.
Large images slow down websites, take longer to share and use storage quickly. Compression does not have to make an image look blurry. A good result comes from balancing three things: dimensions, format and quality.
Start with image dimensions
A 4,000-pixel-wide photo is usually unnecessary when it will appear in a 1,200-pixel-wide article. Reducing dimensions before lowering quality often saves the most space with the least visible change.
- Article images commonly need 1,200 to 1,600 pixels of width.
- Thumbnails commonly need 600 to 900 pixels.
- High-density displays may benefit from twice the displayed dimensions.
Avoid enlarging a small image because resizing cannot create real detail.
Choose the right format
JPG works well for photographs with many colors and gradients. PNG is better for transparency, screenshots and graphics with sharp edges. WebP often produces smaller files and is widely supported by modern browsers.
Converting transparent PNG files to JPG replaces transparent areas with a solid background, so always preview the result.
Pick a quality level
A setting between 75% and 85% is a useful starting point for photos. Images containing small text, product details or precise lines may need a higher setting. Reduce quality in small steps and stop when edges begin to blur or smooth colors become blocky.
A quick ToolNest workflow
- Open Compress image and choose the source image.
- Start around 82% quality.
- Set a maximum width that matches where the image will be used.
- Process, preview and compare the file size.
- If necessary, reduce quality in another small step.
ToolNest processes the image in browser memory. The file is not sent to a processing server, which also makes the workflow suitable for personal images and internal material.
When should you stop compressing?
Avoid repeatedly compressing the same JPG because each encoding pass can remove more detail. Keep an original and create every new version from it. Preserve a high-quality original for printing, professional editing or long-term archiving.