How to Compress an Image
Most compressors give you a quality slider and leave you guessing. That works when you just want a smaller file, but it's useless when a form caps uploads at two hundred kilobytes and you need to land under that exactly — which is why this tool has a second mode. Enter a target size and it encodes the image several times at different quality levels, narrowing in on the highest quality that still fits beneath your limit, then tells you which quality it settled on. No repeated manual attempts, no overshooting. If the target genuinely can't be reached even at minimum quality, the result is flagged rather than silently handed back oversized, and the fix is usually to reduce the dimensions too — which you can do in the same pass with the maximum width field. The before-and-after panel puts the original and the compressed version side by side at full size, because a percentage saving means nothing if the result looks bad, and that is a judgement only your eyes can make. WebP output typically gives another 25 to 35 per cent over JPEG at the same visible quality. Process a whole folder at once, adjust the settings and re-apply to everything, then download individually or as a ZIP. Nothing is uploaded.
Add your images
Drag and drop, paste, or click to browse — multiple at once.
Set quality or target
Pick a quality level, or name the file size you need to hit.
Compare and download
Check the before-and-after, then save or take the ZIP.
How Compression Works
Discarding what the eye misses
JPEG and WebP throw away fine variation that human vision is poor at detecting, particularly in colour and in busy areas. Lowering quality discards more, which is why artefacts first appear around sharp edges and in flat gradients.
Dimensions beat quality
Halving width and height removes three quarters of the pixels — a far bigger saving than any quality setting, with less visible damage. Resize to the size you actually display, then compress.
Common Use Cases
Hit an upload limit exactly
Target mode lands under a form's cap without repeated attempts.
Speed up a website
Smaller images are the biggest single Core Web Vitals win on most pages.
Email attachments
Compress a set of photos so the message doesn't bounce.
Free up storage
Batch-compress an archive of photos you don't need at full quality.
Marketplace listings
Most platforms cap image size per listing.
Faster page builders
Large images slow down editors as well as visitors.
Reduce hosting bandwidth
Smaller files cost less to serve at volume.
Presentations
Cut deck size dramatically by compressing embedded photos.
Tips & Best Practices
Resize first, compress second
Reducing dimensions saves far more than lowering quality, and the result looks better.
80 is the usual sweet spot
Below about 70 artefacts start showing on flat areas and edges; above 90 you mostly add bytes.
Try WebP
It typically gives 25 to 35% smaller files than JPEG at the same visible quality, and every current browser supports it.
Always look at the comparison
A 90% saving is worthless if the image now looks smeared. Judge it with your eyes, not the percentage.
Don't recompress repeatedly
JPEG loss accumulates. Always compress from the original, not from an already-compressed copy.
Keep the original
Compression is irreversible, so archive the full-quality file before replacing it.
Troubleshooting
Target not reachable
Even minimum quality couldn't fit the target at those dimensions. Set a maximum width to shrink the image as well.
The image looks smeared
Quality is too low, or the target is too aggressive. Raise it, or reduce the dimensions instead so quality can stay higher.
Transparency turned white
JPEG has no alpha channel. Choose WebP as the output format to keep transparency.
The file barely shrank
It may already be well compressed. Reducing dimensions is the reliable next step.
Frequently Asked Questions
How do I compress an image for free?
Drop your images above, choose a quality level or a target file size, and download the result — free, no signup and no watermark.
Can I compress to an exact file size?
Yes. Enter a target in kilobytes and the highest quality that fits underneath it is found automatically.
Are my images uploaded to a server?
No. Compression happens entirely in your browser, so your images never leave your device.
What quality should I use?
Around 80 for most photographs. Below 70 artefacts appear; above 90 the file grows without much visible gain.
Should I use JPEG or WebP?
WebP gives 25 to 35% smaller files at the same visible quality and is supported by every current browser.
Why does it say target not reachable?
Even at minimum quality the image couldn't fit your target at those dimensions. Set a maximum width as well.
Does compressing lose quality?
Yes, both formats are lossy. The comparison view lets you judge whether the loss is acceptable.
Can I compress several images at once?
Yes. Add a whole folder and download them all as a single ZIP.
Is there a file size limit?
No. Nothing is uploaded, so the only constraint is your device's memory.
Should I resize as well?
Usually yes. Reducing dimensions saves far more than quality alone and looks better doing it.
What happens to transparency?
WebP keeps it. JPEG has no alpha channel, so transparent areas are filled with white.
Can I undo compression?
No. The discarded detail is gone permanently, which is why you should keep the original.
Does it remove EXIF data?
Yes. Canvas-based processing drops metadata, including any GPS coordinates.
How much smaller will my image get?
Typically 50 to 80% for photographs at quality 80. The readout shows your exact saving.
Why compress an already small image?
Often you shouldn't — if it's already well compressed, the saving will be minimal. Resize instead.
Does it work offline?
Once the page has loaded it runs entirely in your browser, so it keeps working without a connection.
Does it work on phones?
Yes, in any modern browser on Windows, Mac, Android or iPhone with nothing to install.
Is this tool really free?
Completely free, forever — no account, no ads and no premium wall.
100% free · No signup · Processed in your browser · Never uploaded
Last updated: August 2026 · FlipMyFormat Image Compressor
Written and maintained by the FlipMyFormat team · Runs entirely in your browser