To convert a bitmap to PDF, open the BMP in an image application and print or export it as a PDF. For several images, use a tool that lets you check the page order before saving. The important choices are which images are included, how they fit the page, and whether the converter resamples or recompresses them.
Use a PDF for a fixed review sequence, a proof packet or a document containing image pages. Keep the original image files when someone needs to edit or reuse individual photographs. Putting an image in a PDF does not make it sharper, searchable or automatically smaller.
This guide includes a tested two-page ImageMagick conversion and a tested Python fallback. The Windows, macOS and Photoshop routes are application guidance, not claims that we ran those applications for this article. The examples use existing real SendPhoto gallery screenshots saved as BMP inputs; no interface or conversion result was fabricated.
Choose a route
- Windows: print a BMP to PDF
- macOS: combine images with Preview
- Photoshop: create a PDF presentation
- ImageMagick: an ordered batch conversion
- See the actual input and output
- Use the Python fallback
- Check quality and delivery
- Read the FAQ
What changes when you convert a BMP?
BMP is a raster image format: it describes pixels, rather than editable objects or text. Many BMP files are uncompressed, but the format also has compressed variants, including the run-length encoding described in Microsoft’s bitmap compression documentation.
A PDF can contain those image pixels plus page-size information. Depending on the converter and settings, it may preserve the pixels, resize them or encode them with lossy compression. A successful export alone does not tell you which happened.
A multipage PDF also differs from a contact sheet. The first can give each image its own page; the second places several thumbnails on one page. Decide which result the reader needs before selecting a layout.
Windows: print a BMP to PDF
For one BMP, use an installed image application that can open the file and print, such as Paint:
- Open the BMP and check that the whole image appears correctly.
- Open the application’s print dialog, usually with Ctrl+P.
- Select Microsoft Print to PDF, if it is available in your printer list.
- Check paper size, orientation, margins and scaling in the app’s print setup or preview. Avoid a fill/crop setting when every edge must remain visible.
- Print to a new PDF filename, then open that PDF and inspect every page.
The paper layout comes from the application’s print settings. A large bitmap can span more than one page if it is not fitted appropriately. Do not assume that one source file always produces one page.
For several BMPs, some Windows configurations expose a Print action for selected images in File Explorer. Use it only after its preview shows the complete set in the intended order. If the option is absent or the order is difficult to control, use the explicit batch method below instead. Printing separate files to the same PDF filename does not safely append them.
Microsoft documents the PDF printer as a print destination in its printing guidance. If your PDF printer is missing or an app cannot print, follow Microsoft’s application printing troubleshooting rather than installing an unknown converter from a pop-up.
macOS: combine images with Preview
For multiple images, open them together in one Preview window. Apple explains the window behavior in Display several files in one Preview window.
- Open the BMP files in Preview and choose View > Thumbnails.
- Check the sidebar sequence and select the images you want included.
- Choose File > Print and confirm the selection and page count in the print preview.
- Choose the paper size and orientation. Under scaling, Print Entire Image preserves the whole image; Fill Entire Paper can crop it. For one image per page, check the pages-per-sheet setting as well.
- Open the PDF menu in the print dialog and choose Save as PDF.
- Reopen the saved file to check the sequence, edges and orientation.
These settings are described in Apple’s Preview printing guide and Save as PDF instructions. Saving or exporting a single selected image is not the same operation as printing the full selected set.
Photoshop: create a PDF presentation
If you already work in desktop Photoshop, File > Automate > PDF Presentation provides a route for assembling images. Adobe’s PDF Presentation documentation describes adding files and dragging them into order.
- Choose File > Automate > PDF Presentation.
- Use Browse to add files, or add images already open in Photoshop.
- Drag the list into the required order. Remove unwanted duplicates.
- Choose a multipage document for a review packet rather than slideshow presentation behavior.
- Review the output options offered by your installed version and save a new PDF.
- Open it in a PDF viewer and check every page before sending.
Use this route when its assembly controls fit the job, not because it guarantees better quality than every other converter. Verify compression and any downsampling choices in the available export settings. Adobe notes that these presentations are generic PDFs and are rasterized when reopened in Photoshop; keep your editable originals separately.
Do not promise secure circulation simply because a PDF has a password. If you need access restrictions, choose a delivery method and settings appropriate to the material. A recipient who can view a document can still reproduce its contents.
ImageMagick: an ordered batch conversion
The following command was run with ImageMagick 7.1.2-31 on Linux. The two filenames are listed explicitly, so page one is the desktop image and page two is the mobile image. Substitute your own filenames in the intended order and choose an output filename that does not already exist.
magick -version
magick -list policy
magick -units PixelsPerInch -density 150 \
001-desktop.bmp 002-mobile.bmp \
-compress Zip review.pdf
This example assigns a 150-pixels-per-inch scale and uses ZIP compression. It does not request pixel resizing. The resulting pages follow the source image proportions; they are not automatically A4 or Letter. ImageMagick documents density and other command options.
Use explicit file order for important documents. A shell wildcard such as *.bmp normally expands in the shell’s sort order, which may place 10.bmp before 2.bmp. Numbering files 001, 002 and so on helps, but check the resulting list. Case-sensitive systems may also omit .BMP when matching *.bmp. If there are no matches or a named file is missing, stop and correct the input; do not treat a failed command as a completed PDF.
If PDF output is blocked: ImageMagick may report that the operation is not authorized by the security policy. Its security policy documentation explains that allowed formats can be restricted. We reproduced this error with a separate test policy that denied PDF access. The normal system policy was not changed. Use another approved converter or the fallback below; do not disable the machine’s policy wholesale.
Our two-page conversion result
The test inputs were 24-bit RGB BMP copies of two existing screenshots: a 1440 × 1000 desktop gallery view followed by a 428 × 932 mobile view. Together the BMPs occupied 5,516,796 bytes. The ImageMagick PDF occupied 3,238,596 bytes, about 3.24 MB. That reduction is a result for these files and settings, not a promise for every BMP.
The output had two pages:
- Page 1: 691.2 × 480 PDF points, equivalent to 9.6 × 6.67 inches.
- Page 2: 205.44 × 447.36 PDF points, equivalent to 2.85 × 6.21 inches.
Those different page sizes are intentional: each follows its input’s proportions at 150 pixels per inch. A uniform Letter or A4 document needs a separate fit-with-margins layout decision.
We extracted the embedded images with Poppler’s pdfimages and compared their decoded RGB pixel data against the BMP inputs. Both matched exactly, with their original pixel dimensions and page order. We also rendered and visually inspected both PDF pages. This checks this conversion’s pixels and layout; it does not certify every BMP variant, color-managed print workflow or PDF viewer.
Actual PDF page 1 rendered with Poppler. The input was a BMP copy of this existing desktop gallery screenshot. The visible gallery is the image being converted, not a SendPhoto PDF-conversion interface. Open page 1 at full size.
Actual PDF page 2 rendered with Poppler, from a BMP copy of this existing mobile gallery screenshot. The page remains portrait; it has not been stretched to match page 1. Open page 2 at full size.
Download the actual two-page sample PDF. Its gallery buttons are pixels in a static image; they are not interactive gallery controls inside the PDF.
A Python fallback without changing ImageMagick policy
For users comfortable with Python, the script below uses Pillow to decode BMP files and ReportLab to create image pages. It does not invoke ImageMagick or its PDF coder. Install the packages into your chosen Python environment with python -m pip install Pillow reportlab, then save the script as bmp-to-pdf.py.
Run it with an output filename first, followed by the input filenames in page order:
python bmp-to-pdf.py fallback.pdf 001-desktop.bmp 002-mobile.bmp
from pathlib import Path
import sys
from PIL import Image
from reportlab.pdfgen import canvas
from reportlab.lib.utils import ImageReader
if len(sys.argv) < 3:
raise SystemExit('Usage: python bmp-to-pdf.py output.pdf input1.bmp [input2.bmp ...]')
output = Path(sys.argv[1])
inputs = [Path(name) for name in sys.argv[2:]]
if output.exists():
raise SystemExit('Output already exists; choose a new filename.')
for path in inputs:
with Image.open(path) as image:
if image.format != 'BMP':
raise SystemExit(f'Not a BMP file: {path}')
image.load()
pdf = canvas.Canvas(str(output), pageCompression=1, invariant=1)
for path in inputs:
with Image.open(path) as source:
image = source.convert('RGB')
width, height = (value * 72 / 150 for value in image.size)
pdf.setPageSize((width, height))
pdf.drawImage(ImageReader(image), 0, 0, width=width, height=height)
pdf.showPage()
pdf.save()
We ran this with Python 3.12.11, Pillow 12.3.0 and ReportLab 5.0.1. It produced the same two page sizes and exact decoded RGB pixels, in the same order, in a 4,046,359-byte PDF. It also rejected missing arguments, a missing input file and an existing output filename. A conversion error means you should inspect the message and inputs before proceeding.
The script deliberately converts inputs to RGB. It is a simple image-page example, not an archival preservation tool: it does not preserve layers, all source metadata, transparency behavior or a complete color-management workflow. See Pillow’s supported image formats and ReportLab’s image drawing documentation for the underlying tools.
Check quality before delivery
- Count and order: confirm every intended image appears once, in the right sequence. Review the PDF itself, not just the source folder.
- Edges and orientation: check all four edges for cropping and look for accidental rotation or stretching.
- Small details: inspect text and fine lines at useful viewing sizes. A PDF wrapper cannot recover detail absent from the source.
- Print scale: divide image pixels by the placed width or height in inches to calculate effective pixels per inch. Raising a density setting alone does not create new pixels.
- Compression: compare the result against the input if you select a smaller-file preset. JPEG compression and downsampling can alter details; file size alone is not a quality score.
- Filename and instructions: use a clear name such as
portrait-proofs-2026-09-27.pdf, identify the version and tell the recipient how to reference a page when giving feedback.
Keep the original images and the editable working files. For color-critical or commercial printing, ask the printer for its page size, bleed, profile and PDF requirements instead of assuming the review PDF is press-ready.
Bitmap-to-PDF FAQ
Does converting BMP to PDF reduce quality?
It depends on the converter and settings. Our tested ZIP-compressed example preserved the embedded RGB pixels exactly. Other exports may resize images or use lossy compression. Compare your result rather than assuming every PDF conversion is lossless.
Does conversion make text searchable or editable?
Not by itself. Text inside a BMP remains part of the image unless an OCR process adds a text layer. A PDF editor may extract or replace an image, but that is different from recovering editable text or the original layered design.
Is PDF the best way to send photo proofs?
Use PDF when a fixed page sequence helps the review. For many separate photographs, a gallery may make browsing and downloading easier. Our client photo delivery guide covers that decision.
SendPhoto is separate from the conversion step. Use a suitable file-delivery channel for the PDF and SendPhoto’s gallery delivery features for the finished photographs. This tutorial does not claim that SendPhoto converts BMPs or accepts PDFs as gallery images.