How to compress and convert an image
This tool re-encodes images entirely inside your browser using the HTML canvas API — there is no upload, no queue and no account. Drag an image onto the drop area (or click to browse), and it appears on the left as the original while a freshly encoded version appears on the right. Choose an output format, drag the quality slider, and optionally set a maximum dimension; the result and its new file size update so you can dial in the smallest acceptable image. When you are happy, press Download to save it.
Everything is recomputed locally and instantly, so you can experiment freely. The result panel always shows the new dimensions, the new byte size, and the percentage change versus the original — making it obvious when a setting has paid off or gone too far.
Choosing the right format
JPEG is best for photographs and complex images with smooth gradients; it is lossy and has no transparency, so this tool fills any transparent areas with white before encoding. WebP is the modern all-rounder: it typically produces noticeably smaller files than JPEG at the same visual quality and also supports transparency, which makes it excellent for converting bulky PNG screenshots. PNG is lossless and supports transparency, ideal for logos, icons, line art and anything that must stay pixel-perfect — but its files are larger, so reserve it for images that genuinely need it. A common, high-value move is loading a large PNG and exporting it as WebP, often cutting the size by more than half with no visible difference.
Quality and resizing explained
For the lossy formats — JPEG and WebP — the quality slider runs from 1 to 100 and controls how aggressively the encoder discards detail. Values around 75–85 are usually indistinguishable from the original while being much smaller; pushing lower trades visible artifacts for an even tinier file. PNG is lossless, so the slider is hidden when PNG is selected. Resizing is independent of format: set a maximum dimension in pixels and the longest side is scaled down to fit while the aspect ratio is preserved, which alone can dramatically cut the byte size of an oversized photo. Leave the value at zero to keep the original dimensions and only re-compress or convert.
Why a local image tool beats an upload site
Most "free image compressor" sites work by uploading your picture to their servers, processing it there, and sending it back. For a meme that is harmless; for real images it is a privacy problem. Personal photos, screenshots that contain account details, product mockups under NDA, medical or document scans — none of that should be handed to a third party that may store, log or analyze it. Once an image leaves your device you cannot unsend it.
This tool never uploads anything. The image is decoded and re-encoded by your own browser's canvas engine, the same code that renders images on every web page you visit. That also means it works offline, has no file-size cap imposed by an API, and processes images about as fast as your CPU allows. gitime.dev is built on this principle: processing your actual data belongs on your machine, not on someone else's server.
Practical tips
- Shrinking a photo for the web? Try WebP at quality 80 with a max dimension of 1600–2000 px.
- Converting a screenshot? PNG → WebP usually halves the size with no visible loss.
- Need transparency? Use PNG or WebP, not JPEG.
- Email or upload limit? Lower the max dimension first, then ease the quality down until you fit.
- Comparing options? The result panel shows the exact size change for each setting.
Frequently asked questions
- Are my images uploaded anywhere?
- No. Images are re-encoded with the canvas API inside your browser; the picture never leaves your device.
- Which formats are supported?
- JPEG, PNG and WebP, in any direction — load one, export another.
- How does the quality slider work?
- For JPEG and WebP it sets encoder quality from 1 to 100. PNG is lossless, so the slider does not apply.
- Can it resize as well as compress?
- Yes. Set a maximum dimension and the longest side scales to fit, preserving aspect ratio. Zero keeps the original size.