Convert
Shrink image files, privately
Compress images with adjustable quality and optional max width, locally in your browser, with the size saving shown.
For the best results: Start at 75% quality, usually indistinguishable for photos at a fraction of the size. Set a max width too: resizing saves more than quality tweaks.
Advanced settingsoptional, defaults work well
Processed entirely in your browser, your photos are never uploaded, logged, or stored.
What is Image Compressor?
Image Compressor is a free file converter that compresses JPG, PNG, and WebP images with adjustable quality and optional resizing, showing the size saved. Each image is decoded and re-encoded by your own browser's graphics engine, so your photos are never uploaded to a server. There is no queue, no watermark, and no account to create, and it keeps working with your connection off.
- ✦Runs entirely in your browser. Nothing you enter is ever uploaded
- ✦No account, no sign-up, and no data leaves your device
- ✦Works offline once the page has loaded
See it in action
A job portal rejects anything over 100 KB, and the phone photo of a signed certificate is 1.1 MB.
What you drop in
certificate.jpg (1,117 KB), advanced setting "Compress to target size" set to 100 KB
What you get
certificate-compressed.jpg at 94 KB, under the limit with room to spare. The tool searched for the highest quality that fits rather than guessing.
Tip: Give the target field the portal's real limit and let the search do the work: in testing it landed at 94 KB against a 100 KB target instead of overshooting to grainy. Very large images are fine too, a 96-megapixel panorama compressed in about 3 seconds.
Use cases
What people use it for
Get a phone photo under a job portal upload limit without emailing it to yourself first.
Compress a batch of property listing photos so the page loads quickly on mobile data.
Shrink blog hero images before deploying so readers on slow connections are not left waiting.
Who uses Image Compressor?
Web developers
trim page images before a release so performance scores hold up, without piping client assets through an external service
Real estate agents
squeeze whole shoots of listing photos down to portal-friendly sizes in one batch, with no per-file limits
Job applicants
fit certificates and headshots under strict application form size limits while the documents stay on their own computer
How it works
- 1Choose your files. They open in your browser, not on a server.
- 2Your device converts, compresses, or resizes them locally, with no upload.
- 3The converted files download straight back; nothing is kept anywhere.
Tips for the best results
- Resize before you compress; shrinking dimensions removes far more bytes than squeezing quality ever will.
- Try two or three quality settings and keep the highest one that looks identical to the original.
- Leave text-heavy screenshots as PNG rather than forcing them through heavy JPG compression.
- Compress copies for sharing and keep the untouched originals for future editing.
- Watch the size-saved readout across a whole batch to spot the handful of files doing most of the damage.
FAQ
Frequently asked questions
What is the difference between lossy and lossless compression?
Lossless compression repacks the data more cleverly while keeping every pixel identical, which is how PNG works. Lossy compression, used by JPG and lossy WebP, permanently discards detail your eye is unlikely to notice, achieving far smaller files. The quality slider on this tool controls how aggressive that discarding is, so it only affects lossy formats.
What happens when I compress a PNG?
PNG is lossless, so re-saving it as a PNG would barely shrink it. In the default Auto mode this tool re-encodes a PNG as lossy WebP at your chosen quality, which is where the big savings come from, and the result downloads with a .webp extension. If the destination needs a JPG instead, pick Always JPG under Advanced settings.
How does JPG make photos so much smaller?
Two tricks. First, chroma subsampling: human vision is far more sensitive to brightness than to color, so JPG stores the color information at a lower resolution than the brightness, saving space almost invisibly. Second, it breaks the image into small blocks and discards the fine detail within each one, with the quality setting deciding how much gets thrown out.
When do compression artefacts start to show?
Sharp edges, small text, and smooth gradients give the game away first: text grows fuzzy halos, gradients develop banding, and flat areas turn blocky. Ordinary photos with natural texture hide compression remarkably well, so they tolerate much lower settings. Preview the result, and if edges look rough, nudge the quality up a step until the defects disappear.
Do my photos get uploaded while compressing?
Never. The encoder runs inside the page on your own hardware, and the size-saved figure is calculated right there too, so nothing about your images, not even a byte count, reaches any server. Pull out the network cable after the page loads and the compressor keeps working exactly as before. Sensitive documents and personal photos stay entirely yours.
How can I reduce a photo's file size without losing quality?
Resize it first. A photo four thousand pixels wide displayed in an eight-hundred-pixel slot carries mostly wasted data, and scaling down sheds that invisibly. Then apply moderate lossy compression, which at sensible settings is indistinguishable from the original. The two steps together routinely cut files to a small fraction of their size.
Is this an AI tool?
No. It uses standard, deterministic image encoders: the same photo at the same settings produces exactly the same result every time. For this job that is a genuine advantage, because the output is instant, predictable, and computed entirely on your device rather than sent to a remote system you have to trust.
How do I compress a photo for email?
Drop the photo in, enable resizing to bring the longest side down to a screen-friendly width, and set the quality slider somewhere in the middle range. The size-saved readout shows the result immediately. A multi-megabyte camera photo typically becomes light enough to attach several at once without bouncing off mailbox limits.
Are there any usage limits?
None. Everything is generated locally in your browser, so there is no server cost, no metering, and no daily cap, use it as many times as you like, completely free.
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