Turn an image into an outlined sticker
Add a thick sticker-style outline around your image by automatically detecting the opaque areas. Requires a PNG image with a transparent background for a clean result.
How it works
The tool analyzes your image's transparency (alpha) channel to precisely locate the opaque shape, then "expands" that area by a number of pixels equal to the chosen thickness (a dilation). The expanded area, filled with the outline color you picked, is placed behind your original image: the result is a uniform outline that follows the contours of your shape exactly, like a real die-cut sticker.
Why doesn't the outline appear on my image?
If the imported file has no real transparency (for example a JPEG, or a PNG with an opaque white background), the tool treats the whole image as a single opaque area: the outline then ends up entirely outside the image edges, where it can't be seen. Use a PNG with a truly transparent background (alpha channel) for a correct result.
Does the outline follow the curves of my shape perfectly?
The outline is computed with a fast two-pass dilation (horizontal, then vertical), which gives a slightly squared approximation rather than a perfectly circular one. At moderate thicknesses (up to 20-25px), the difference is invisible to the eye; on very thick outlines and very rounded shapes, slight corners may appear at sharp changes of direction.
100% local processing: outline detection and rendering happen entirely in your browser — your image is never sent to a server.