Compress an image
Reduce the weight of your images for a site or an email: set the quality and compare the result side by side, or fix a target weight and let the tool find the best quality that fits. A WebP at quality 80 is often 25 to 35 % lighter than a JPEG at the same visual quality. The compression is local, so a photo you compress never leaves your machine.
- 100% local
- Free · no account
- Instant result
This tool runs entirely in your browser — nothing is sent to a server.
The weight of images accounts for most of the weight of a web page, and therefore of its loading time. Compressing a photo properly often divides its weight by five with no difference perceptible to the eye — quality 80 in JPEG is almost always indistinguishable from quality 100.
This tool displays the two versions side by side so you judge the trade-off yourself. You can adjust the quality with the slider, or set a maximum weight in kilobytes and let the tool find by bisection the best quality that fits the budget — handy when a form imposes a size limit.
How it works
Type the figures or drop the file you want to process — the tool checks them as you go.
Everything is computed directly in your browser. Nothing is sent to a server.
The result appears instantly, with the detailed breakdown ready to copy, download or keep.
Why use this tool
No account, no download, no limit: the result appears as soon as you enter your data.
Every rule, algorithm and check reflects what we use ourselves every day at Flexina.
The calculations follow the official standards, and the step-by-step detail lets you double-check the outcome.
What does running it locally bring you?
Files, figures and documents never leave your device: nothing is stored, nothing is sent.
Once the page is loaded, you can cut the network: the tool keeps working.
No upload, no account, no third-party server in between: results stay fast and fully private.
Frequently asked questions
What quality should I choose?
Between 75 and 85 for a photo destined for the web: the loss is invisible and the weight saving considerable. Below 60, artefacts become visible on flat areas and edges. Compare the two displayed images to decide.
JPEG or WebP?
WebP produces files 25 to 35 % lighter than JPEG at equivalent quality and is recognised by all current browsers. Prefer JPEG only if the file must be opened by older software.
How do I respect a size limit imposed by a form?
Use the “target weight” mode: enter the limit in kilobytes and the tool automatically finds the highest quality that fits the budget, by testing several successive encodings.
Are my photos sent anywhere?
No. The compression uses your browser’s graphics engine: your images never leave your device.