PNG to SVG for Laser Cutting: A Practical Guide for Glowforge, LightBurn and xTool

You have a PNG (a logo, a piece of clip art, a drawing you scanned) and you want to cut or engrave it with your laser. The problem is that your Glowforge, xTool, or LightBurn setup expects a vector file, not a raster image. PNG files are made of pixels; laser cutters follow mathematical paths. You need to bridge that gap.

This guide walks through why vectorization is necessary, how it works, and what a quality laser ready SVG actually looks like so you can judge whether your conversion is ready to run.

Why you can't just send a PNG to your laser

A PNG is a grid of colored pixels. Your laser controller (LightBurn, Glowforge's interface, xTool Creative Space) needs to know the path to cut: a precise X/Y trajectory the laser head follows. Pixels don't carry that information. When you import a raster image directly, you get one of two outcomes: a rasterized engrave (the laser traces every line of pixels, which works for engraving photos but isn't a cut), or an error.

A vector SVG, by contrast, describes shapes as mathematical outlines: curves and lines defined by coordinates. The laser controller reads those outlines as cut paths, which means you get clean, sharp edges regardless of how you scale the design.

How vectorization works

Vectorization is the process of analyzing a raster image and tracing its edges into vector paths. The algorithm looks at contrast boundaries between adjacent pixels and fits smooth curves (Bézier paths) along those edges. The result is an SVG made of closed shapes that approximate the original image.

The quality of the vectorization depends on two things: the quality of the source image and the settings used during tracing. High-contrast, simple designs (logos, silhouettes, bold clip art) vectorize cleanly. Complex photographs with gradients, noise, or fine detail produce messy, node-heavy SVGs that are hard to cut.

What makes a laser ready SVG

Not all SVGs are suitable for laser cutting. A well-prepared file has:

Closed paths for cutting lines. Every shape the laser should cut all the way through needs to be a closed path, a loop with no gaps. Open paths (lines that don't connect back to their start) produce partial cuts or just engraving lines.
No embedded raster images. Your SVG should contain only vector paths. Some export tools produce SVGs with the original PNG still embedded inside. The laser controller can't cut those.
Separate layers for cut vs engrave. If your design has both cut lines and engrave areas, keep them on separate SVG layers or as separate color fills. LightBurn uses color to assign operations (red = cut, blue = engrave, etc.).
A reasonable node count. Over-traced images can have thousands of nodes on a single shape. This slows down your controller software and produces jerky laser motion. Simplify paths until you have the minimum nodes that preserve the shape.
No tiny isolated shapes. Vectorization often produces small specks and islands from noise in the source image. These translate to tiny burned dots or micro-cuts that weaken your material. Remove anything smaller than your minimum feature size.

Cutting vs engraving: getting the settings right

When you import your SVG into LightBurn or Glowforge, you'll assign each layer an operation:

Line / Cut: The laser follows the path outline at cutting power. Use this for shapes where you want the laser to cut all the way through the material.
Fill / Engrave: The laser rasters back and forth inside the shape at lower power to darken or ablate the surface. Use this for areas you want to mark but not cut through.
Offset Fill: A hybrid mode. The laser follows progressively offset outlines inward. Good for thick engraved areas on wood or acrylic.

For most converted images, you'll use cut for the outer silhouette and fill/engrave for interior details. Think of the two-layer approach: one layer is the cut boundary, the other is the engrave detail.

Checking your file before you fire the laser

Running a design without checking it first is how you waste material. Before you load the file into your laser controller, look for:

Open paths: In LightBurn, use Edit → Select Open Shapes to find them, then Edit → Close Path or Edit → Auto Join Selected Shapes where appropriate. In Inkscape, inspect suspect paths with the Node tool and close gaps before exporting.
Tiny shapes below minimum feature size: Delete anything smaller than about 2mm × 2mm (or your material's minimum reliable cut size). These don't cut cleanly and weaken the surrounding material.
Double-stacked paths: If vectorization traces both sides of a thick line, you end up with two overlapping outlines that cause double-cuts. Delete one or merge them.
Node count: High node counts (>500 nodes per shape) indicate over-tracing. Run a simplify pass.

Glowforge users: Glowforge's importer is less strict than LightBurn, but it still can't cut open paths as outlines. They'll be treated as engrave lines. Always close your cut paths before uploading.

A quick workflow

Start with the highest-contrast version of your image (increase contrast in any photo editor if needed).
Convert to SVG using ButterySpace's Image → SVG mode. Choose "Logo / B&W" for clean cut designs, or "Color art" if you want to preserve multiple color regions.
Read the geometry check that runs on the traced result. It flags open paths, tiny islands, and high node counts in plain English so you can spot problems before you download. (Need repairs applied automatically? Run the SVG through Fix SVG mode, which adds a missing viewBox, closes open paths, and strips anything a laser can't read.)
Download the SVG and import it into LightBurn or Glowforge.
Assign cut/engrave operations per layer and run a framing pass before firing.

The most common mistake is skipping step 3 and going straight to the laser. Ten seconds of checking saves you the cost of a ruined piece of walnut.