Fastest way: the image to PDF converter, which runs in your browser.
Ways to convert images to PDF
- In the browser: use the image to PDF converter on this site. It works on every device, does not upload your files, and gives you control over the order, the page size and the quality.
- Windows: select the images in File Explorer, right-click, choose Print, pick Microsoft Print to PDF as the printer, and choose the layout and paper size. The images go into one PDF.
- Mac: open the images in Preview, show the thumbnails in the sidebar, select all, then choose File, Print, and Save as PDF. In Preview you can also drag the thumbnails to change the order.
- iPhone and iPad: in Photos, select the photos, tap Share, then Print. Pinch outward on the preview of the pages to open it as a PDF, then use Share and Save to Files.
- Android: open the photo, choose Print from the menu, and select Save as PDF. Scanner apps and Google Drive can also scan pages into a PDF.
- Command line: see the commands below.
The steps in the menus can differ a little between versions of the systems, so look for Print and Save as PDF if a menu has a different name.
Choosing a page size
| Page size | Millimetres | Inches | Points | Pixels at 300 dpi |
|---|---|---|---|---|
| A4 | 210 × 297 | 8.27 × 11.69 | 595 × 842 | 2480 × 3508 |
| Letter | 215.9 × 279.4 | 8.5 × 11 | 612 × 792 | 2550 × 3300 |
| Legal | 215.9 × 355.6 | 8.5 × 14 | 612 × 1008 | 2550 × 4200 |
| A3 | 297 × 420 | 11.69 × 16.54 | 842 × 1191 | 3508 × 4961 |
| A5 | 148 × 210 | 5.83 × 8.27 | 420 × 595 | 1748 × 2480 |
Use A4 in most of the world and Letter in the United States and Canada, so that the recipient can print the PDF without scaling. Use Same as image when you want no white space, for example for a long screenshot or an image of unusual shape.
Resolution
Printing quality depends on the number of pixels per inch (dpi) when the image is on the page. 300 dpi is sharp for photos and for most print, and 150 dpi is enough for documents that are mostly read on a screen. A full A4 page at 300 dpi needs about 2480 × 3508 pixels. More pixels than that make the file larger without any visible gain.
JPG or PNG inside a PDF
- A JPEG can be stored in a PDF without being compressed again, so there is no extra loss. It is the best choice for photographs.
- A PNG is stored with lossless compression, which keeps text and lines sharp and keeps transparency. It is the best choice for screenshots, diagrams and logos, but it makes photographs very large.
The PNG to PDF page starts in lossless mode, and the JPG to PDF page copies the JPEG data as it is.
Keeping the PDF small
- Reduce the maximum image size. 2000 to 3000 pixels on the longest side is enough for A4.
- Use Medium quality for photographs that will only be viewed on a screen.
- Crop or resize the images before you convert them, or run them through the image compressor.
- Use black and white scans for text documents. They are much smaller than color scans.
Photos that show sideways
Phones store many photos in one fixed direction and add a rotation note to the file. Programs that read the note show the photo correctly, but many PDF tools ignore it, and the photo appears sideways in the PDF. A good converter turns the picture first. The photos to PDF page does this.
Image PDF and text
A PDF made from images shows pictures of pages. The text in it cannot be selected, searched or read aloud by a screen reader. If you need searchable text, run the PDF through an OCR program. If you need an accessible document, start from the original text where possible.
Command line tools
# img2pdf (Python): keeps JPEG data without recompression pip install img2pdf img2pdf page1.jpg page2.jpg -o output.pdf # ImageMagick magick page1.jpg page2.png output.pdf
ImageMagick decodes and encodes the images, so a JPEG may lose a little quality, and its security policy can block PDF output on some systems.
Problems and fixes
- The pages are in the wrong order: sort the files by name, with leading zeros (01, 02 ... 10), before you add them.
- White bars on a page: the image has a different shape than the page. Use Fill, or the page size Same as image.
- The PDF is huge: reduce the maximum image size and the quality.
- A HEIC photo does not open: convert it to JPG, or set the iPhone camera to Most Compatible.