How image compression works
Image compression reduces a file's size by storing its pixels more efficiently. Lossy formats like JPG and WebP discard visual detail you are unlikely to notice, which shrinks photos dramatically. Lossless formats like PNG keep every pixel exactly, so they compress less but never degrade. This tool detects your image's format automatically and re-encodes it in the browser, showing you the before and after size instantly.
This image compressor runs entirely in your browser. Drop in a image file, adjust the quality until the preview looks right, and download the smaller version — no uploads, no sign-up, and no watermark.
How to use it
1. Drop your image onto the drop zone or click to browse.
2. Use the before/after slider to compare the original with the compressed result.
3. Drag the quality slider until the file is as small as you want while still looking good.
4. Download the image. Everything is processed on your device.
Choosing the right quality
For photographs, a lossy quality of 75–80% is almost always the right balance of size and clarity. For screenshots, logos, and graphics with sharp edges or transparency, a lossless format preserves quality but compresses less. If a lossless file is still too big, converting it to WebP is usually the best next step.
Match the format to the picture: JPG or WebP for photos, PNG for graphics and transparency, and WebP when you want the smallest file that still supports transparency.
Common mistakes to avoid
A few habits quietly ruin image quality or waste file size:
- Compressing from an already-compressed copy instead of the original, which stacks up quality loss. - Pushing lossy quality so low that edges look blocky just to save a few kilobytes. - Using a lossless format for a photograph, or a lossy format for a logo with sharp text. - Forgetting that resizing a large image to the dimensions you actually display it at often saves more than compression alone.
Frequently asked questions
Does compressing an image reduce its quality?
It depends on the format. Lossy formats (JPG, WebP) trade a little detail for a much smaller file — imperceptible at high quality settings. Lossless formats (PNG) keep every pixel exactly, so quality never drops; they simply compress less.
What is the best format for a small file size?
For photographs, WebP usually produces the smallest file at a given quality, followed by JPG. For graphics, screenshots, and images with transparency, PNG is best for quality but WebP is smaller. This tool keeps your original format by default, and you can convert if you want more savings.
Are my images uploaded to a server?
No. All compression happens locally in your browser using the canvas engine — your images never leave your device, so it is safe to compress private or work photos.
Should I compress or resize an image to shrink the file?
They solve the problem differently. Compression lowers the encoding quality so the file is smaller at the same pixel dimensions; resizing reduces the dimensions themselves. If an image is far larger than the space it is shown in, resize it first and then compress — that gives the smallest file with the best on-screen quality.
Is this tool free?
Yes — compressing images here is completely free, with no watermark, no account, and no limit on how many you process.
Will compression change the image dimensions?
No. Compression only changes how the pixels are stored, not the width and height. If you also want smaller dimensions, use the resize tool, which often saves even more space.