Quick format guide
There is no format that produces the smallest file for every image. The best choice depends on what the image contains, whether transparency matters, and which formats the destination accepts.
| Format | Often a good fit | Keep in mind |
|---|---|---|
| JPEG / JPG | Photographs and broad compatibility | Uses lossy compression and cannot keep transparent pixels. |
| PNG | Screenshots, diagrams, sharp edges, or transparency | Uses lossless compression; a photo saved as PNG can be much larger than a JPEG. |
| WebP | Web images where the destination supports it | Supports lossy or lossless compression and transparency, but check the destination's requirements. |
Choose based on the image
- For a photograph, compare JPEG and WebP output and inspect fine detail before choosing.
- For a screenshot, chart, or graphic with text, try PNG when crisp edges matter. WebP is another option if the destination accepts it and the result looks right.
- For a logo or cutout with transparent areas, use PNG or WebP. JPEG does not support transparency.
- If you are not sure what a form, app, or website accepts, check its upload instructions before converting.
Compare the actual output
Changing a filename extension does not convert the image. A conversion re-encodes image data, and the output size and appearance depend on the encoder and its settings. Compare the preview and measured file size, and keep the source if it matters.
shrinkpixel checks the browser's encoded MIME type before offering a download. Browser support can vary, so a requested output format may not be available in every browser.