Uwarp

Or try an example

Outline width (px)

Works best on transparent PNGs (stickers, logos, cutouts). For edge maps of photos see Edge Detection; for soft bloom try Glow Effect.

Help Us Improve

—

(—)

Outline an image online

Free image outliner: add a black or colored outline to a PNG, photo, or picture. Adjust width and style, preview instantly, download — outline maker in your browser.

What is an image outliner?

An image outliner (also searched as outline maker, image outline generator, picture outline maker, photo outline maker, and outline generator) adds a colored stroke around a subject so you can outline an image, outline a photo, or create a picture outline for stickers and graphics. People look for “outline image”, “black outline”, “image to outline”, “how to make an outline”, and “border outline” when they need a clear silhouette edge — not a full photo-to-sketch conversion. This tool dilates the PNG alpha mask, paints the ring in your chosen color, and exports PNG in the browser. For detecting photo edges as a filter map see /image-edge-detection; for soft bloom see /glow-effect-image.

Image outliner features

Add a custom outline to PNG subjects and cutouts.

  • Width & color

    Dial stroke thickness and pick any hex — including black outline presets.

  • Outer-only mode

    Skip holes so letter counters and cutouts stay open.

  • Soft edge & halo

    Fade the outer pixels or create a soft halo stroke.

  • Canvas expansion

    Pads the PNG so outer outlines are not clipped.

  • Before / after

    Compare the outlined picture with the original.

  • Private PNG export

    Client-side outline maker — download free.

How to outline a picture online

Create an image outline in four steps.

  1. Upload

    Drop a PNG, JPEG, or WebP — transparent PNGs work best.

  2. Set the stroke

    Choose width and outline color (try black outline first).

  3. Tune options

    Enable outer-only for logos; soft edge or halo for gentler borders.

  4. Download

    Save the outlined PNG.

Tips for cleaner outlines

Better results from the outline maker.
  • 01

    Start from a transparent PNG

    Remove the background first (/make-image-transparent or /remove-background-image) for a true subject outline.

  • 02

    Use outer-only on text and logos

    Keeps the insides of letters open while thickening the outer contour.

  • 03

    Match width to resolution

    1–8 px for small icons; 10–30 px for large sticker PNGs.

  • 04

    White outline on dark scenes

    Switch from black outline to white when the subject sits on dark backgrounds.

Outline tools compared

How this free image outliner stacks up.

  • Online PNG Tools (add outline to PNG)

    Competitor ranking for outline image, image outliner, and outline maker. This page matches that intent with width, color, outer-only, soft edge, and halo options — offline in the browser.

  • Edge Detection (/image-edge-detection)

    Produces an edge map of the whole photo. Use Image Outliner when you want a solid colored stroke around a cutout.

  • Glow Effect (/glow-effect-image)

    Soft bloom around bright areas — different from a hard outline stroke.

  • This image outliner

    Alpha-based PNG outline generator with black/color presets. Best for stickers, logos, and picture outlines.

Great for

When you need a clear picture outline or photo outline.

  • Stickers & memes

    Add a bold black outline so cutouts pop on any background.

  • Logos & icons

    Thicken thin marks with a matching or contrasting stroke.

  • Signatures

    Bold a transparent signature PNG without redrawing it.

  • Product cutouts

    Give ecommerce PNGs a clean border outline for catalogs.

Why use this image outliner

A focused outline generator without desktop editors.

  • 100% free

    No account or watermark on the PNG.

  • Built for search intent

    Targets image outliner, outline image, outline maker, and photo outline queries.

  • Alpha-aware

    Follows the real silhouette of transparent PNGs.

  • Privacy first

    Images never leave your device.

Technical details

How this outline image tool works.
Masking
Opaque pixels (alpha ≥ 16) define the subject silhouette.
Stroke
Circular morphological dilation minus the original mask.
Outer-only
Flood-fills exterior transparency from the canvas border.
Output
Expanded transparent PNG with outline behind the original pixels.

Sources & References

References on outlines, alpha masks, and Canvas compositing.
  • “The alpha channel represents the degree of transparency of a pixel.”
    — Wikipedia — Alpha compositing

    Alpha compositing: This image outliner finds subject edges from alpha, dilates that mask, and paints the ring as a stroke around the PNG. en.wikipedia.org/wiki/Alpha_compositing

  • “Dilation is one of the basic operations in morphological image processing.”
    — Wikipedia — Dilation (morphology)

    Morphological dilation: Outline width is produced by dilating the opaque mask, then keeping only the newly covered pixels as the stroke. en.wikipedia.org/wiki/Dilation_(morphology)

  • “PNG supports an optional alpha channel for transparency.”
    — Wikipedia — PNG

    PNG format: Transparent PNGs are ideal inputs for an outline maker — stickers, logos, and cutouts keep a clean silhouette. en.wikipedia.org/wiki/PNG

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

    Canvas API: Outlining runs client-side with getImageData / putImageData — no server upload. developer.mozilla.org/en-US/docs/Web/API/Canvas_API

Frequently Asked Questions

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