Compress Image Online — Reduce Size in KB
Set a target file size in KB or adjust quality. Compare the actual result for websites, email, and upload forms.
1. Upload Image
Drop your image here to compress
or click to browse
JPG, PNG, WebP, GIF, HEIC up to 10MB
Why Compress Images?
Faster Websites
Smaller images load faster, improving user experience and Google PageSpeed scores.
Save Storage
Reduce storage costs on servers, cloud drives, and your device.
Faster Sharing
Create smaller images for email, messaging and social uploads. Check the destination’s size limit.
Reduce image size in KB instead of guessing quality
Choose Target file size to enter a KB ceiling, or Quality to control the tradeoff yourself. Presets cover 20KB, 50KB, 100KB, 200KB and 500KB. Check the actual output bytes and the target-status message before uploading the result.
JPG and WebP support quality-based compression. PNG uses lossless encoding in quality mode; target mode may convert it to JPG and remove transparency. Keep your source when transparency or exact dimensions must be retained.
What the Quality Slider Is Actually Doing
JPEG compression does not simply 'reduce quality' in a general way. It breaks the image into 8 × 8 pixel blocks, converts each block from pixel values into frequency information, and then divides those frequencies by numbers taken from a quantization table. High frequencies — fine texture, sharp edges, small details — get divided by large numbers and often round down to zero, which is where the space saving comes from.
The quality slider scales that table. At 90 the divisors are small and almost everything survives. At 40 they are large and entire categories of detail vanish. This is why the damage from over-compression looks so distinctive: you see the 8 × 8 blocks themselves appear in smooth areas like sky and skin, because within each block there is no longer enough information to describe a gradient.
It also explains why compression behaves so differently depending on content. A photograph of foliage is nearly all high-frequency detail and resists compression; a studio portrait against a plain backdrop is mostly low-frequency and compresses beautifully. Two images at identical settings can differ threefold in size for this reason alone.
Choosing a Quality Setting
Rough guidance for photographic content. Graphics and screenshots tolerate compression far worse.
| Quality | Visual result | Suitable for |
|---|---|---|
| 95–100 | Indistinguishable from original | Archival copies, print masters |
| 85–90 | No visible loss in normal viewing | Portfolio work, client delivery |
| 75–85 | Excellent — the usual sweet spot | Websites, social media, email |
| 60–75 | Slight softening on close inspection | Thumbnails, hitting size limits |
| 40–60 | Visible artifacts in flat areas | Only when a hard limit forces it |
| Below 40 | Obvious blocking and colour banding | Best avoided entirely |
Compression Damage Accumulates
Every time a JPEG is opened, changed and saved again, it goes through the whole quantization process afresh — on top of the losses already baked in. Ten rounds of saving at quality 85 looks considerably worse than one round at 60, even though 85 sounds like the safer number. This is generation loss, and the way to avoid it is to keep an untouched original and always export from that rather than repeatedly editing and re-saving the compressed copy.
Compress or Resize?
They solve different problems, and reaching for the wrong one is the most common mistake.
- ✓The dimensions are already correct for where the image will be used
- ✓You need a modest reduction — say 40–60% smaller
- ✓The image is displayed at full size and must stay sharp
- ✓You are optimising a batch of already correctly-sized web images
- ✕The image is far larger than it will ever be displayed
- ✕You need a dramatic reduction, such as a phone photo down to 100KB
- ✕Compression alone is not getting you under the limit
- ✕You are uploading a 4000px photo to fill a 600px slot
Formats Respond Very Differently
Compressing a PNG is a fundamentally different operation from compressing a JPEG. PNG is lossless, so 'compressing' it means finding a more efficient lossless encoding — reducing the colour palette, optimising how rows are filtered — and the savings are usually modest, perhaps 10–30%. Nothing is discarded.
JPEG and lossy WebP genuinely discard information, which is why their savings are so much larger. WebP tends to reach a given visual quality in roughly 25–35% fewer bytes than JPEG, so if the destination is a website and you can serve WebP, converting will usually beat compressing the JPEG harder.
For screenshots, logos and anything containing text, the right answer is usually not to apply lossy compression at all. Those images belong in PNG or lossless WebP, where the letterforms stay clean; pushing them through a JPEG encoder produces visible coloured fringing around every edge.
Frequently Asked Questions
How do I compress an image for email?
Upload your image, set the quality to around 70–80%, and download the compressed version. Most email clients recommend images under 1MB. Our compressor can reduce most photos to well under that limit.
Can I compress an image to a specific file size like 100KB?
Choose Target file size and enter the limit in KB. The tool searches quality settings and may reduce dimensions. Check actual output bytes and whether the target was met.
Will compressing reduce visible quality?
Lossy compression can change fine details at any quality setting. Start around 80, compare the export at its intended display size, and increase quality if text, edges or textures deteriorate. Savings depend on the source.
What formats can I compress?
JPG, PNG, and WebP are supported. JPG compresses best for photos; PNG is better for graphics and logos.
Is my image stored after compressing?
No. Your image is processed immediately and deleted from our servers. We never store or share your files.