When this tool is useful
Modest crispness after resizing or scanning when the source already contains usable detail.
How local processing works
A local pixel filter amplifies differences around edges according to the selected strength, then re-encodes the image.
How to use it
- Prepare Sharpen an image: Work from a copy and confirm strength, existing noise, high-contrast edges, faces, prior compression, dimensions, and output quality. Keep the source unchanged.
- Apply Sharpen an image: Process locally in the browser. A local pixel filter amplifies differences around edges according to the selected strength, then re-encodes the image.
- Download and verify: Save under a new name. Compare at 100% rather than fit-to-screen, inspect halos and flat areas, and confirm the new file does not merely look harsher.
Important limitations
Sharpening cannot recover missing focus or resolution and can amplify noise, JPEG blocks, halos, and skin texture.
Verify the downloaded result
Compare at 100% rather than fit-to-screen, inspect halos and flat areas, and confirm the new file does not merely look harsher.
Private by design
Your files stay in this browser. The tool does not upload the source or output to our servers.
Questions and answers
When should I use Sharpen an image?
Modest crispness after resizing or scanning when the source already contains usable detail.
What does Sharpen an image change?
A local pixel filter amplifies differences around edges according to the selected strength, then re-encodes the image.
Which limits and settings matter?
strength, existing noise, high-contrast edges, faces, prior compression, dimensions, and output quality. Sharpening cannot recover missing focus or resolution and can amplify noise, JPEG blocks, halos, and skin texture.
How do I verify the result?
Compare at 100% rather than fit-to-screen, inspect halos and flat areas, and confirm the new file does not merely look harsher.