phototostl
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Image to STL Converter

Create a free STL relief in your browser, or switch to Full 3D to generate an AI model with credits.

  • 6 conversion modes
  • Runs in your browser
  • No signup, no credits
  • Free download
Conversion tier

Drop a file here

JPG / PNG / GIF / BMP / WEBP / HEIC · One file, up to 20 MB

Illustration of an elephant photograph beside a half-solid, half-wireframe 3D elephant model

How to convert an image to STL

From an image to a model you can inspect before printing.

  1. 1. Choose and prepare your photo

    Start with a sharp image and a recognizable subject: an evenly lit portrait, simple drawing, or clear silhouette. Crop away distractions.

  2. 2. Convert the image and inspect the STL

    Use the free converter. Decoding, brightness sampling, mesh generation, and export happen in your browser.

  3. 3. Check the model in your slicer

    Use a slicer compatible with your printer and start from its matching printer and material profiles. Import the STL and check its dimensions before arranging it on the build plate.

Why use phototostl for image to STL conversion

One image. Six ways to shape it.

Choose a heightmap, color heightmap, silhouette extrusion, color-region extrusion, cookie cutter or lithophane. Each free mode uses your image pixels or outline to build an STL in your browser.

Start with contrast you can see

Choose a sharp image with distinct tones or a clean silhouette. Heightmap modes turn tones into surface height; extrusion modes follow the image mask and color regions. Transparent pixels and the background color controls can isolate an outline, but they do not identify people or objects with AI.

Set the size, then check the slice

Set the image dimensions and thickness for the selected conversion type. Keep the aspect ratio locked or set width and height independently. Bases, frames and keyrings can extend the finished dimensions. Open the exported STL in a slicer and inspect small features before printing.

Choose how shape and color are used

The six free modes create heightmaps, colored heightmaps, silhouette extrusions, color-region extrusions, cookie cutters and lithophanes. Color modes show surface colors in the preview. Standard STL stores geometry; optional RGB and BGR STL encodings are nonstandard color extensions and may not be recognized by your slicer.

Illustration of six ginkgo-leaf outputs: heightmap, color heightmap, extrusion, color-region extrusion, cookie cutter and lithophane

A photo made for the light.

Make a flat, curved, cylindrical or spherical lithophane. Adjust its shape and thickness range, then inspect the preview before exporting.

Test light transmission before a full print

Lithophane mode makes dark image areas thicker by default and offers flat, arc, cylinder and sphere shapes. Test a small piece with a suitable translucent material and a light behind it. Invert reverses the thickness direction; it is not required for the normal backlit mapping. The preview cannot predict how your material transmits light.

Illustration of flat, curved, cylindrical and spherical fern-pattern lithophanes

From outline to cookie cutter.

Use the silhouette of your image to define a cookie cutter. Adjust the cutting edge, wall and base, and check the resulting outline in the preview.

Illustration of a flower outline and its hollow cookie cutter with a reinforced base

What this tool does not do

The six free modes build geometry from the pixels and outlines you provide. They do not infer hidden sides or identify the subject with AI. Background removal uses transparency or color tolerance, which may also remove matching parts of the subject. Full 3D is a separate paid AI module; inspect either result and the slicer preview before printing.

Technical limits

High is the default detail. Original detail preserves source resolution up to 1536 pixels on the longer side, including raw 16-bit PNG height values. Low, Medium and High target 256, 384 and 768 samples without enlarging small originals. Preview and download use the same mesh. Larger sources require an explicit lower detail choice. Increasing physical width does not recover missing image detail. Heightmaps make light areas higher by default; Lithophane mode makes dark areas thicker by default. Invert reverses the selected mapping. Complex color regions, edges and attachments use more memory; a resource limit can require lower detail or simpler settings.

Conversion time

Conversion time depends on the mode, detail setting, image and device. Complex outlines, color regions, edge shaping and attachments take more work than a simple heightmap. There is no server queue. Preview and download use the same mesh; progress and errors are shown while the browser works.

Choosing the thickness

For heightmaps, Base thickness sets the backing and Total height sets the upper height limit, including that backing; Total height must not be below Base thickness. Extrusion and cutter modes use their depth and wall settings. Lithophane mode has its own minimum and maximum thickness, with dark areas thicker by default. Test small prints because material and thickness affect strength and light transmission.

Supported image formats and STL output

Input Images

  • JPG
  • PNG
  • WebP

Choose JPG, PNG, GIF, BMP, WEBP or HEIC, up to 20 MiB per image. Both Color heightmap and Extrude colors accept an optional overlay.

3D Output

STL

Download a binary STL. Standard STL stores geometry and is the default. RGB and BGR options use nonstandard color extensions, so preview colors may not appear in your slicer.

FAQ: image to STL and 3D printing

What to expect from the free conversion modes, local processing and your first print.