daytics™
Drag & drop images here, or click to select (multiple files supported)
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How to Compress Images Online
- Upload your images — Drag and drop one or more image files into the upload area above, or click to open your file browser and select them manually. JPG, PNG, and WebP formats are all supported.
- Set your quality level — Use the quality slider to choose a value between 10% and 100%. For web use, 70-85% is recommended. Lower values produce smaller files but may introduce visible artifacts.
- Choose an output format — Select "Same as input" to keep the original format, or switch to JPG or WebP for potentially smaller file sizes.
- Review the results — Each compressed image appears below with the original size, new size, and percentage saved clearly displayed.
- Download your compressed images — Click the Download button next to each image to save the optimised version to your device.
How Image Compression Works
Image compression reduces file size by removing redundant or less important visual data from the image. Our tool uses the HTML5 Canvas API built into your browser to re-encode images at a lower quality level. When you load an image, it is drawn onto an invisible canvas element, and then exported as a new file with your chosen quality setting applied.
For JPG and WebP formats, this process uses lossy compression, which means some image data is permanently discarded to achieve smaller files. The quality slider controls how aggressively data is removed. At 80%, the algorithm keeps most of the visual detail while discarding information that the human eye is unlikely to notice, such as subtle colour gradients in busy areas of the image.
PNG compression works differently because it is a lossless format. When outputting to PNG, the file size reduction comes from more efficient encoding rather than data removal. This is why PNG files are generally larger than their JPG or WebP counterparts, but they preserve every pixel of the original image perfectly.
Frequently Asked Questions
Does compressing an image reduce its quality?
Lossy compression (used for JPG and WebP) does reduce quality slightly, but at settings between 70% and 85% the difference is virtually invisible to the human eye. The key is finding the sweet spot where file size drops significantly while visual quality remains acceptable for your use case. You can always preview the result before downloading.
Are my images uploaded to a server?
No. Our image compressor runs entirely in your browser using the HTML5 Canvas API. Your images never leave your device, which means your files remain completely private and secure. There is no upload step, no waiting for server processing, and no risk of your images being stored elsewhere.
What is the best image format for the web?
WebP is generally the best format for web images because it offers superior compression compared to both JPG and PNG while supporting transparency. JPG remains a strong choice for photographs where transparency is not needed, and PNG is ideal when you need lossless quality or transparency in older browsers that do not support WebP.
What quality setting should I use for compression?
For most web images, a quality setting between 70% and 85% provides an excellent balance between file size and visual quality. Photos for social media can go as low as 60% without noticeable degradation. For print or professional use, keep quality above 90% to preserve fine details and colour accuracy.
What is the difference between lossy and lossless compression?
Lossy compression permanently removes some image data to achieve smaller file sizes, which is how JPG and WebP compression work. Lossless compression reduces file size without discarding any data, preserving perfect quality. PNG uses lossless compression, which is why PNG files are typically larger than JPG or WebP equivalents.
Can I compress multiple images at once?
Yes. Our tool supports batch processing, allowing you to drag and drop or select multiple images at the same time. Each image is compressed individually using your chosen quality setting and output format, and you can download each result separately from the results list.
