About the Sharpen Image
Sharpen Image adds crispness to photos that came out a little soft, such as a scan, a resized picture or a shot taken in a hurry. It uses an unsharp mask, the same method photo editors have used for decades: the tool blurs a copy of your picture, finds where the real picture differs from the blur (the edges), and pushes those edges a bit further apart. You control how strong the effect is, how wide the edges it looks at are, and which tiny differences to ignore. Everything runs in your browser, so your photo is never uploaded. It cannot rebuild detail that was never captured: a badly out-of-focus or motion-blurred photo will only look slightly better, and too much sharpening makes bright halos around edges.
Updated September 2026
How to use the Sharpen Image
- 1Choose Select photo, or drop a JPG, PNG or WebP file on the page.
- 2Start with the Normal button, then fine-tune Amount and Radius while watching the preview.
- 3Tap Original to compare with the untouched picture, and raise Threshold if smooth areas such as skin or sky look grainy.
- 4Pick a file type and choose Download sharpened image.
What the three sliders do
Amount is how hard the edges are pushed. Around 50 to 120 percent suits most photos; above 200 percent the effect becomes obvious and is meant for very soft sources. Radius is the width of the edge the tool reacts to. A small radius of about 0.5 to 1 pixel crisps up fine detail such as hair, text and leaves. A larger radius of 2 to 4 pixels adds local contrast to bigger shapes and is a better match for large, high-resolution photos.
Threshold is a safety net. It tells the tool to skip differences smaller than the chosen number, so flat areas with gentle noise stay calm while clear edges still get sharper. If a portrait looks rough after sharpening, leave Amount where it is and raise Threshold to 5 to 15 instead.
Brightness only or each colour?
In Brightness only mode the tool sharpens how light or dark each pixel is and leaves colour balance alone. This is the safer choice for photos of people, sky and anything with soft colour changes, because it does not create coloured fringes along edges. Each colour mode sharpens red, green and blue separately. It can look a little punchier on graphics and screenshots, but on photos it may show tiny colour halos when pushed hard.
Getting a good result
- Sharpen last. Resize or crop first, because resizing a sharpened picture softens it again.
- Judge at 100 percent. Zoom in on the downloaded file: the on-screen preview of a big photo is reduced, so it can hide halos.
- Watch for halos. A bright or dark line next to an edge means the radius or amount is too high.
- Save as PNG if you will edit the picture again, or JPG for a small file to share.
- Already sharp photos gain little. Sharpening works on softness, not on real blur, so a photo that missed focus cannot be saved by it.
On a phone or on a computer
The tool works the same on both. A phone photo of 12 megapixels is processed at full size in a few seconds; while it works the button shows Working. Pictures over 8,192 pixels on a side or 16.7 million pixels are refused with a message, because phone browsers run out of memory on them. Shrink those first with Image Resizer and sharpen the smaller copy. If the picture is too small to sharpen well, enlarge it with Image Enlarger, and hide fine detail with Blur Image.
Features
- Unsharp mask with amount up to 300%, radius 0.5 to 4 px and a threshold
- Brightness-only mode to avoid coloured edges, or each-colour mode
- Light, Normal and Strong starting points
- Before and after preview on the same spot
- Transparency in PNG and WebP pictures is kept
- Saved at the original size as JPG, PNG or WebP
- Runs in your browser: photos stay on your device
Frequently asked questions
Can this unblur a blurry photo?
Only a little. Sharpening raises contrast along edges that are already there, which makes a slightly soft photo look clearer. If the picture is badly out of focus or smeared by movement, the detail was never recorded and no setting can bring it back.
Is my photo uploaded anywhere?
No. The photo is opened and processed by your own browser, and the result is saved straight to your device. You can check this by watching that no upload happens while you use the page.
What settings should I start with?
Press Normal, which is 100 percent amount with a 1.5 pixel radius and no threshold. For a small web image try Light, and for a large, soft scan try Strong. Then adjust one slider at a time and compare with the Original view.
Why are there bright outlines around edges?
Those are halos, the usual sign of too much sharpening. Lower the amount or the radius until they disappear. Raising the threshold does not remove halos; it only protects flat areas.
Will the file size or dimensions change?
The dimensions stay exactly the same. The file size can grow a little, especially as JPG, because sharper edges are harder to compress. Choose PNG to avoid any further compression loss.
Does it keep transparent backgrounds?
Yes for PNG and WebP. Transparency is never changed, only the colour of visible pixels. JPG has no transparency, so transparent areas turn white when you save as JPG.
Does it work on a phone?
Yes. The controls are sized for touch, and the page works in a phone browser. Very large photos may be slow or may be refused, in which case make them smaller first.