Stroke image edges
Trace detected outlines in colour over your photo. Nothing is uploaded.
- Your files are never uploaded
- Processed on your device
- Works offline
- Free, no sign-up
Drop your images here
Images · up to 10 files, 100 MB each
or paste with Ctrl+VLive preview
Settings
Applies to JPG and WebP only. PNG is always lossless.
How it works
Add your images
Choose JPG, PNG, WebP, GIF, BMP, AVIF or HEIC images to outline on your device.
Check the conversion options
Pick the edge colour and line width, then inspect the result preview.
Convert and download
Save your IMG results individually or download the converted images together as a ZIP.
Neon traces over real edges
Stroking scans your photo for brightness edges, the boundaries where light meets dark that define shapes, and paints glowing strokes directly over them in your chosen colour. A red default recalls markup pens and neon signage, but any colour works: cyan for tech diagrams, gold for festive portraits, white for subtle sketch definition. Line widths from one to twelve pixels range from hairline etching to bold comic inking.
Because strokes follow genuinely detected contours rather than a uniform filter, flat skies and smooth walls stay clean while faces, buildings and objects gain crisp graphic definition. The original photo shows through untouched between the lines, so the result reads as an enhancement, not a replacement.
Markup, memes and diagrams
Teachers circle apparatus in lab photos with bright strokes that survive photocopying, and reviewers trace UI elements in screenshots for feedback that cannot be missed. Meme makers and thumbnail designers use thick neon outlines to make subjects punch through crowded feeds at tiny sizes.
Large images are fitted within 4096 pixels before detection, noted on the result row. Edge detection runs on true luminance, so even softly lit boundaries are found and traced at full resolution.
Traced locally, shared globally
Edge maps reveal the shapes inside your photos, so computing them anywhere but your own device would be an unnecessary exposure. This stroker performs all detection and painting inside the browser tab, meaning your pictures are never uploaded, profiled or retained by any outside system.
Without a network round trip there is no queue, no login and no watermark diluting your lines. Downloaded results are fresh files free of the hidden GPS tags embedded in many camera originals.
Questions
Are my images uploaded to detect edges?
No. Edge detection and painting happen in your browser, so images never leave your device.
How are edges found?
The tool measures brightness changes between neighbouring pixels. Strong boundaries are traced; smooth areas are left alone.
Will strokes cover my photo?
Only the outlines are painted in your colour and width. Everything between the edges shows the original photo.
Is it free?
Yes. Free to use, with no sign-up, no watermark and no daily limits.
Related tools
More free tools that run on your device. No uploads