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pdfconversionapi

XCF to ICO API

POST an .xcf to /v2/convert/xcf/to/ico and get an icon file with one 32-bit image of the merged layers. Canvases larger than 256 px are fitted into 256 × 256; send ImageWidth for a smaller icon.

Endpoint
POST /v2/convert/xcf/to/ico
Accepts
xcf
Sample timing
45 ms median of 5 runsHow we measure
Request size
Up to 10 MB on the Free plan or 100 MB on paid plans, all files together

Request and response

Every sample below ran against the API before this page was published. Set PDFCONVERSIONAPI_KEY to your key and run it as is.

curl -sS -X POST \
  https://api.pdfconversionapi.com/v2/convert/xcf/to/ico \
  -H "Authorization: Bearer $PDFCONVERSIONAPI_KEY" \
  -F File=@gull-rock-lighthouse.xcf \
  --form-string ImageWidth=64 \
  -o response.json

# FileData is base64. Save the first file in converted/,
# or print the JSON error.
if jq -e '.Files' response.json > /dev/null; then
  mkdir -p converted
  name=$(jq -r '.Files[0].FileName' response.json)
  jq -r '.Files[0].FileData' response.json \
    | base64 --decode > "converted/$name"
else
  cat response.json
fi
200 OK45 ms median1 file, 4.3 KB
{
  "ConversionCost": 1,
  "ConversionTime": 0.045,
  "Files": [
    {
      "FileName": "gull-rock-lighthouse.ico",
      "FileExt": "ico",
      "FileSize": 4395,
      "FileData": "AAABAAEAQDAAAAAAIAAVEQAA…"
    }
  ]
}

Response from our test run on 2026-11-03. ConversionTime shows the median of 5 runs. FileData is shortened here; the real response carries the whole file as base64.

The sample, converted

The same file the code sends. Download the input and the output and compare them yourself.

First page of gull-rock-lighthouse.ico, rendered by the API
Input
gull-rock-lighthouse.xcf (203 KB)
Output
gull-rock-lighthouse.ico (4.3 KB)
Source
A 400 x 300 harbor poster we drew and wrote as a layered XCF file ourselves: 11 layers, including a two-layer group, a layer mask, Multiply and Screen modes and a hidden guide layer. (CC0-1.0). How it was made
Made by
2026-11-04, API build 9eeeb0640aba

Parameters

Send these as form fields next to the file. Names are case-insensitive. If you set one of the documented options below that we don't support yet, the request fails with a 400 that names it instead of returning a file made without it.

ParameterWhat it does
ImageWidthintegerIcon width. The sample sends 64, so the 400 × 300 poster becomes a 64 × 48 icon of 4,395 bytes. Values above 256 end up at 256.Values: 1–20000
ImageHeightintegerIcon height; with ImageWidth, a box the canvas is fitted into.Values: 1–20000
ScaleProportionsboolean, default truefalse with both sizes gives a square icon from a non-square canvas: 300 × 300 was cut down to a 256 × 256 entry.
ScaleIfLargerboolean, default falsetrue keeps a canvas smaller than the requested size as it is.
ScaleImageboolean, default truefalse crops the top-left area instead of scaling the whole canvas.
ColorSpaceenum, default defaultgray (24,665 bytes at 256 × 192) or monochrome (3,017 bytes, with color values only black or white) icon colors; still stored as a 32-bit image.Values: default, rgb, gray, monochrome; cmyk returns 400
FileNamestringName of the .ico file; favicon gives favicon.ico.
StoreFileboolean, default falsetrue returns a 3-hour link in place of base64.

What carries over, and what doesn't

Kept

  • The merged look of the layers, scaled with a Lanczos3 filter
  • Transparency: the icon image is 32-bit RGBA, so a GIMP canvas with a transparent background gives an icon with a transparent background
  • The canvas proportions: a 4:3 poster gives a 4:3 icon (256 × 192 by default) unless you set both sizes

Lost or not yet supported

  • Multiple sizes. The .ico holds a single image, at the size you asked for.
  • Square shape for non-square canvases, unless you send both sizes with ScaleProportions=false.
  • Detail at small sizes: at 64 × 48 the poster's subtitle is no longer readable.

Limits

  • One XCF per request. The canvas may hold up to 67,108,864 pixels (8,192 × 8,192): 16,384 × 4,096 gave a 256 × 64 icon, 8,193 × 8,192 gets a 422.
  • Requests up to 10 MB on the Free plan or 100 MB on paid plans, all files and fields together.
  • 120 seconds per conversion, then 504.
  • The icon image is at most 256 × 256 pixels.

Where teams use it

Favicons from a GIMP logo

Site logos are often kept as layered GIMP files. Converting the .xcf with ImageWidth=32 or 48 gives a favicon.ico without an export step, straight from the master.

Application and shortcut icons

Windows shortcuts and installers use .ico files. Draw the icon on a square GIMP canvas and send it with ImageWidth=256, the largest size one ICO entry can hold.

Questions

Which sizes does the .ico contain?

One. The sample request gives a single 64 × 48 entry; with no size sent, the poster gives one 256 × 192 entry. To ship 16, 32 and 48 px versions, make one request per size and combine them with an icon tool.

How is the image stored inside the icon?

As a PNG image inside the ICO container, 8 bits per channel with alpha. The file has no bitmap-style entry, so a program that only reads the older bitmap entries will not show it.

What if my GIMP canvas is not square?

The icon keeps its proportions, so a 400 × 300 canvas gives 256 × 192. For a square icon, make the canvas square in GIMP or send ImageWidth, ImageHeight and ScaleProportions=false to stretch it.

Convert your first XCF file in a minute.