Uwarp

Or try an example

Stroke width
Alpha cutoff

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Add an image stroke to a PNG

Add an image stroke online free. Outline a PNG with a colored stroke, preview the border, download a transparent PNG. Local-first, no sign-in.

What is image stroke?

An image stroke is a colored outline drawn around a PNG or cutout. People search for “image stroke” when they want to add a stroke to a logo, sticker, or transparent PNG. This free local-first tool dilates the opaque shape and paints a stroke ring behind the original pixels.

Image Stroke features

Local PNG editing for this task.

  • Live preview

    See the result before you download.

  • PNG download

    Keep transparency when the format supports it.

  • Local-first

    No cloud upload.

  • Free

    No account required.

How to image stroke

Three steps in the browser.

  1. Upload

    Drop a PNG or other raster image.

  2. Adjust

    Tune the controls until the preview looks right.

  3. Download

    Save the PNG result.

Tips

Cleaner results.
  • 01

    Use a clear source

    Sharp edges and solid backgrounds work best.

  • 02

    Compare before/after

    Use the preview slider to check the change.

  • 03

    Stay under the upload limit

    Very large files may need a smaller source first.

Great for

Everyday PNG workflows.

  • Stickers and logos

    Prep assets for apps and marketplaces.

  • Quick edits

    No desktop suite required.

  • Private files

    Keep images on your device.

Why use this tool

A focused free browser editor.

  • Free

    No signup.

  • Local-first

    No upload for processing.

  • Fast

    Preview updates as you change settings.

Technical notes

How this page works.
Input
PNG and other common rasters up to the shared upload limit.
Output
PNG download from a canvas encode.
Engine
Browser Canvas 2D pixel processing.
Privacy
Client-side only.

Sources & References

References for PNG and canvas editing.
  • “PNG supports an alpha channel for transparency.”
    — Wikipedia — PNG

    PNG: Transparent PNGs are the usual input and output for this tool. en.wikipedia.org/wiki/PNG

  • “The Canvas API provides a means for drawing graphics via JavaScript and the HTML canvas element.”
    — MDN Web Docs — Canvas API

    Canvas API: Edits run with getImageData / drawImage in the browser. developer.mozilla.org/en-US/docs/Web/API/Canvas_API

Frequently Asked Questions

Quick answers about this tool—open a question to read more.