JPG to PDF: Page Sizes, Quality and Scanning Tips

Everyone eventually needs to send photographed documents as one PDF — a signed form, a receipt, an ID, a set of whiteboard shots. The conversion is easy; getting a document that prints correctly and does not weigh 40 MB takes two decisions.

Decision one: page size

Match image size makes each page exactly as large as its picture. Perfect for photo books and full-bleed output, wrong for paperwork: pages end up different sizes and print unpredictably.

A4 or Letter gives one uniform page and centres each image inside a margin. This is what you want for anything a human will print, sign or file. Add a 20–25 pt margin so nothing lands in the printer's unprintable border.

Decision two: resolution

A phone camera produces 4000 px wide images. Printed on A4 that is about 480 dpi — far beyond what any office printer resolves, and four times the file size of the 300 dpi that is genuinely archival. For document scans, 200–300 dpi across the page width is the sweet spot: roughly 1700–2500 px for A4.

Practical recipe

Resize the photos to about 2000 px wide with the batch resizer, then build the document with JPG to PDF using A4 pages. A ten-page scan lands around 3–5 MB instead of 40 — small enough to email, sharp enough to print.

Photographing documents well

• Shoot straight down; perspective distortion cannot be fixed later in a PDF.
• Diffuse daylight beats flash — flash creates a hotspot in the middle of the page.
• Fill the frame with the page so you are not throwing away resolution on the table.
• Check focus on the smallest text before you take twenty more shots.

Afterwards

Wrong page order? Split and rebuild with the splitter and merger. Need the images back out of a PDF someone sent you? PDF to JPG does the reverse at the resolution you choose.