Skip to content
pdfconversionapi

PSD to BMP API

POST a .psd to /v2/convert/psd/to/bmp to get an uncompressed BMP back in the JSON, 32-bit when the art has see-through pixels. The sample scales the sticker with ImageWidth=200: 200 × 150 pixels at 4 bytes each plus a 122-byte header, 120,122 bytes in all.

Endpoint
POST /v2/convert/psd/to/bmp
Accepts
psd
Sample timing
89 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/psd/to/bmp \
  -H "Authorization: Bearer $PDFCONVERSIONAPI_KEY" \
  -F File=@night-market-sticker.psd \
  --form-string ImageWidth=200 \
  -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 OK89 ms median1 file, 117 KB
{
  "ConversionCost": 1,
  "ConversionTime": 0.089,
  "Files": [
    {
      "FileName": "night-market-sticker.bmp",
      "FileExt": "bmp",
      "FileSize": 120122,
      "FileData": "Qk061QEAAAAAAHoAAABsAAAA…"
    }
  ]
}

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 night-market-sticker.bmp, rendered by the API
Input
night-market-sticker.psd (173 KB)
Output
night-market-sticker.bmp (117 KB)
Source
A layered event sticker we drew for this site: 400 x 300 pixels, 8 bits per channel, transparent around the sticker, with seven layers including a soft shadow, a Screen-blended moon, a two-layer text group and a hidden draft stamp. Written as a PSD by our own script from the published file format specification. (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
ImageWidthintegerPixel width after the layers are merged. Because BMP is not compressed, size follows area: 400 px wide is 480,122 bytes, 200 px is 120,122.Values: 1–20000
ImageHeightintegerPixel height; with a width as well, a box the 4:3 canvas is fitted into.Values: 1–20000
ScaleProportionsboolean, default truefalse lets the width and height stretch the sticker.
ScaleIfLargerboolean, default falsetrue leaves the canvas alone when the request would enlarge it.
ScaleImageboolean, default truefalse crops from the top left rather than resizing.
ImageResolutionintegerStored as pixels per meter in the header: 300 wrote 11,811, which is 300 dpi. Without it the fields are 0.Values: 10–800
ColorSpaceenum, default defaultgray makes every visible pixel gray but keeps the 32-bit layout and the alpha, so the file size does not change.Values: default, rgb, gray, monochrome; cmyk returns 400
FileNamestringBase name of the BMP; night-market-sticker.bmp by default.
StoreFileboolean, default falsetrue returns a link valid for 3 hours instead of base64.

What carries over, and what doesn't

Kept

  • Transparency: the alpha byte of each pixel is kept, with an alpha mask in the header; the 200 × 150 sample's 2,465 clear pixels stay clear (10,195 at full size)
  • Exact merged pixels: decoded, the BMP equals the PNG route's output for the same PSD
  • The 300 ppi setting, only if you send ImageResolution=300
  • Readability: all three readers we tried, the operating system's own image tool included, opened the 32-bit file with its alpha

Lost or not yet supported

  • Compression. Every pixel takes 4 bytes, so the full-size sticker is 480,122 bytes against 177,604 for the PSD.
  • Layers, 16-bit depth and the color profile.

Limits

  • One PSD per request.
  • Requests up to 10 MB on the Free plan or 100 MB on paid plans, all files and fields together.
  • Up to 100,000,000 pixels after flattening, or 413.
  • Resize targets from 1 to 20,000 px per side.
  • 120 seconds per conversion, then 504.
  • Pixel layers, masks, groups and blend modes are tested; type layers, smart objects and layer effects are not yet.

Where teams use it

Tools that read only BMP

Some Windows utilities, embedded display tool chains and older imaging software open BMP and nothing else. Convert the PSD from your build or upload step instead of exporting by hand.

Raw pixels for test fixtures

An uncompressed BMP is easy to read byte by byte, which makes it handy as expected output in image-processing tests: 4 bytes per pixel in a fixed order after a 122-byte header.

Questions

Does the BMP keep transparency?

Yes. It is a 32-bit BMP whose header declares an alpha mask, and the clear corners of the sticker have alpha 0. Under alpha 0 those pixels store black (0, 0, 0), so a program that ignores BMP alpha shows black corners.

Can I get a 24-bit BMP without alpha?

Yes, when the PSD has no see-through pixels: an opaque 64 × 48 test PSD came back as a 24-bit BMP with the 40-byte header, 9,270 bytes. The sticker has clear corners, so it stays 32-bit, and AlphaColor does not change that. To flatten transparent art onto a color you choose, use the JPG or PNM route.

Does TransparentColor work for BMP?

No. It is applied for PNG, GIF, TIFF, WebP and TGA, not BMP: #1E2A4A returned the same bytes as no value.

Convert your first PSD file in a minute.