How do I turn an image into a sketch?

Use Choose a photo or drop a supported file on the stage. Pick Pencil for shading, Pencil + edges for shading with outlines, or Edges for an outline. Set edge weight to 1 for black outlines on white, then adjust threshold to keep stronger or weaker lines. Compare Before, After or Split, and press PNG or JPEG to save the result.

Does it use AI to draw the sketch?

No. It is a fixed pixel filter: gray scale, invert, blur, color dodge and Sobel edges, worked in whole numbers. It turns changes in brightness into tones and lines, and it cannot add strokes, hatching or detail that the photo does not have.

Why are parts of my sketch blank white?

Flat areas come out paper white by design: where the photo is evenly toned, a pixel's gray matches its blurred surroundings and the color dodge gives exactly 255, and smooth gradients come out close to white. Raise the contrast to darken the pencil tones, raise the blur radius to widen the shading, or lower the edge threshold so weaker edges are drawn.

What do the blur radius and edge threshold numbers mean?

The blur radius is in the photo's own pixels: the inverted gray is averaged over 2r + 1 pixels across and then down, three times, which approximates a Gaussian blur. The threshold is on the 0 to 255 gray scale: a straight step of d gray levels scores d, so at 30 a step of 30 levels or more is drawn and weaker ones are dropped.

Does the saved sketch keep the photo's size and transparency?

Yes. The PNG and the JPEG are both the photo's own width and height in pixels. The PNG keeps the photo's alpha channel, so a cut-out stays cut out; a JPEG has no transparency, so transparent areas are laid on white, and it is saved at quality 0.92.

Will the same photo always give the same sketch?

Yes, for the same pixels and settings: every step is whole-number arithmetic, so the result is identical pixel for pixel whether it ran in the background worker or on the page. Two different browsers can decode the same JPEG very slightly differently, and a changed input pixel can change the sketch around it.

How large a photo can it sketch?

Photos up to 16,777,216 pixels (16.7 megapixels, such as 4096 x 4096) and 16384 pixels on a side open, which covers a 12 megapixel phone photo at 4032 x 3024 and a 16 megapixel camera photo at 4608 x 3456; a 24 megapixel photo at 6000 x 4000 needs saving smaller first. The size is read from the file's header before it is decoded, because the photo and its sketch, both at full size, have to fit in the tab's memory on a phone as well as a computer. HEIC and AVIF files need saving as JPEG or PNG first, and a GIF gives its first frame.

Can I use this sketch software on a phone or computer?

Yes, in a current browser that supports picture decoding and canvas. There is nothing to install and your photo is processed locally. The tool remembers settings when browser storage is available, but does not store your photo or sketch. PNG saving needs CompressionStream; JPEG is available if PNG compression is unavailable.

Image to Sketch

Choose a PNG, JPEG, WebP, GIF or BMP photo up to 16.7 megapixels. Turn it into a grayscale pencil sketch, an edge outline or both, adjust the controls, and compare before and after. Download the result as PNG or JPEG at its original pixel size. The core converter is free, needs no account and processes your photo in this browser.

Turn a photo into a pencil or edge sketch

PNG, JPEG, WebP, GIF or BMP up to 16.7 megapixels. It is sketched in this browser and never uploaded.

Choose a photo

Size out: no photo yet

Blur radius: 8 px

Edge threshold: 30 of 255

Sample pixel: none yet

A uniform gray 128 imageany blur, any threshold
every pixel comes out 255, paper white, and no edge is drawn
Straight steps of 20 and 60 gray levelsedge threshold raised from 10 to 40
the 20-level edge disappears and the 60-level edge stays
A transparent 30 x 20 px PNGsaved as PNG, then as JPEG
the PNG is 30 x 20 px with the same alpha on every pixel; the JPEG is 30 x 20 px with transparent areas on white

Common questions

How do I turn an image into a sketch?: Use Choose a photo or drop a supported file on the stage. Pick Pencil for shading, Pencil + edges for shading with outlines, or Edges for an outline. Set edge weight to 1 for black outlines on white, then adjust threshold to keep stronger or weaker lines. Compare Before, After or Split, and press PNG or JPEG to save the result.
Does it use AI to draw the sketch?: No. It is a fixed pixel filter: gray scale, invert, blur, color dodge and Sobel edges, worked in whole numbers. It turns changes in brightness into tones and lines, and it cannot add strokes, hatching or detail that the photo does not have.
Why are parts of my sketch blank white?: Flat areas come out paper white by design: where the photo is evenly toned, a pixel's gray matches its blurred surroundings and the color dodge gives exactly 255, and smooth gradients come out close to white. Raise the contrast to darken the pencil tones, raise the blur radius to widen the shading, or lower the edge threshold so weaker edges are drawn.
What do the blur radius and edge threshold numbers mean?: The blur radius is in the photo's own pixels: the inverted gray is averaged over 2r + 1 pixels across and then down, three times, which approximates a Gaussian blur. The threshold is on the 0 to 255 gray scale: a straight step of d gray levels scores d, so at 30 a step of 30 levels or more is drawn and weaker ones are dropped.
Does the saved sketch keep the photo's size and transparency?: Yes. The PNG and the JPEG are both the photo's own width and height in pixels. The PNG keeps the photo's alpha channel, so a cut-out stays cut out; a JPEG has no transparency, so transparent areas are laid on white, and it is saved at quality 0.92.
Will the same photo always give the same sketch?: Yes, for the same pixels and settings: every step is whole-number arithmetic, so the result is identical pixel for pixel whether it ran in the background worker or on the page. Two different browsers can decode the same JPEG very slightly differently, and a changed input pixel can change the sketch around it.
How large a photo can it sketch?: Photos up to 16,777,216 pixels (16.7 megapixels, such as 4096 x 4096) and 16384 pixels on a side open, which covers a 12 megapixel phone photo at 4032 x 3024 and a 16 megapixel camera photo at 4608 x 3456; a 24 megapixel photo at 6000 x 4000 needs saving smaller first. The size is read from the file's header before it is decoded, because the photo and its sketch, both at full size, have to fit in the tab's memory on a phone as well as a computer. HEIC and AVIF files need saving as JPEG or PNG first, and a GIF gives its first frame.
Can I use this sketch software on a phone or computer?: Yes, in a current browser that supports picture decoding and canvas. There is nothing to install and your photo is processed locally. The tool remembers settings when browser storage is available, but does not store your photo or sketch. PNG saving needs CompressionStream; JPEG is available if PNG compression is unavailable.

A fixed pixel filter, not generative drawing, built from gray scale, an inverted blur, a color dodge and Sobel edges: in one browser the same picture and settings give the same sketch every time. It turns changes in brightness into pencil tones and lines and cannot draw, generate or recover detail the photo does not hold, so flat areas come out paper white. The saved file keeps the photo's pixel size; a PNG keeps its transparency and a JPEG puts it on white.