Two ways to compress
Upload forms, email providers and website builders all have size limits, and phone photos often weigh several megabytes. This tool re-encodes your images to make them lighter, in one of two modes:
- Quality — move the slider from 10% to 100% (75% by default). Lower means a smaller file with more visible compression artifacts.
- Target file size (KB) — type the size you need, such as 100, 200 or 500 KB. The tool finds the highest quality that fits under that size for each image.
Results appear as soon as the images are read and update whenever you change a setting. Each file shows its size before and after and the percentage saved, and the preview shows the compressed version so you can judge the quality before downloading.
How the target size works
JPG and WebP files get smaller as quality goes down, but not in a predictable way, so the tool tests: it first tries 95% quality, and if the file is too big it runs a binary search between 40% and 95% to find the highest quality that fits. Below 40%, blocky artifacts become obvious, so instead of going lower the tool reduces the pixel dimensions in proportion to how far off the size is and searches again. The final dimensions and quality are shown under the preview. If the target is so small that no reasonable result fits, you get the smallest version found and the row says the target couldn’t be reached.
Output format and resizing
| Save as | When to pick it |
|---|---|
| Auto | JPG stays JPG and WebP stays WebP. PNG, HEIC, AVIF and others become JPG — or WebP if the image has transparent areas. Where the browser can’t write WebP (Safari), Auto saves JPG and says so. |
| JPG | Opens everywhere: forms, email, Windows and Mac. Transparent areas turn white. |
| WebP | Usually smaller than JPG at the same visual quality and keeps transparency. Best for websites. Needs a browser that can write WebP (Chrome, Edge, Firefox). |
Resize (longest side) caps the dimensions at 3840, 2560, 1920, 1280 or 800 pixels before compressing (images are never enlarged). A 4000-pixel phone photo shown on a website rarely needs more than 1920 pixels, and halving the width and height leaves a quarter of the pixels, which usually cuts the file size by more than half. For exact sizes for a given social network, use the Social Media Image Resizer.
Tips for the smallest files
- For websites, convert to WebP: see JPG to WebP, and why images save as WebP for what the format is good at.
- Check a photo’s pixel dimensions and weight first with Check Image Size.
- Re-encoding doesn’t copy EXIF metadata, so camera details and GPS location are removed as a side effect. To strip metadata without recompressing, use Remove EXIF Data.
Private and offline
Compression runs in your browser with the Canvas API; iPhone HEIC photos are decoded with a WebAssembly module when the browser can’t read them itself. Your images are never uploaded, there is no limit set by us on the number of files, and the page keeps working offline once loaded.