How the PDF is built
This guide explains how the images you add become PDF pages, how page size, orientation and margins interact, and how the size limit decides how much quality each page keeps. It ends with a worked example of turning ten phone photos into one A4 PDF small enough to email.
Every image you add becomes one page, in the order shown on screen. Each image is encoded as a JPEG with a white background, so transparent areas in a PNG come out white. The image is then placed on its page, scaled to fit inside the margins without cropping or stretching, and centred. If the image has a different shape from the page, the leftover space stays white.
Scaling works in both directions. A small image on an A4 page is enlarged to fill the printable area, which can look soft when printed. A large photo is shrunk to fit, but the full-resolution image is kept inside the PDF unless the size limit forces it smaller, so you can still zoom in.
The whole document is assembled in your browser. Nothing is uploaded, and the result downloads as a single file. It is named after the image when there is only one, "images.pdf" when there are several, or whatever you type in Output name.
Step by step
- Drop your images on the page. JPG, PNG, WebP and HEIC from a phone all work, as do most other image formats.
- Put them in order by dragging the cards or using the arrows.
- Click Edit on any image that needs cropping or rotating. Cropping a photo of a document to the paper edge removes the table or floor around it.
- Choose a Page size. Fit to image makes each page the shape of its photo; A4, US Letter, US Legal and A5 give standard paper pages.
- With a paper size, choose Orientation: Auto turns each page to landscape when its image is wider than it is tall, while Portrait and Landscape apply to every page.
- Choose a Margin. Small is the default and suits most documents.
- In the output options, either set Quality, or turn on Limit PDF size and enter a target such as 2 MB.
- Press Create PDF and download the result.
Page sizes and margins
| Setting | Size | Typical use |
|---|---|---|
| A4 | 210 × 297 mm | Documents and forms almost everywhere outside North America |
| US Letter | 8.5 × 11 in (216 × 279 mm) | Documents in the United States and Canada |
| US Legal | 8.5 × 14 in (216 × 356 mm) | Contracts and long forms in the United States |
| A5 | 148 × 210 mm | Booklets, receipts, half-page handouts |
| Fit to image | The image size, plus the margin | Photo albums and screenshots viewed on screen |
| Margin: None | 0 | Edge-to-edge pages for screen viewing |
| Margin: Small | 0.25 in (about 6 mm) | General documents; the default |
| Margin: Medium | 0.5 in (about 13 mm) | Pages you will print on a home printer |
| Margin: Large | 0.75 in (about 19 mm) | Pages you will hole-punch, bind or annotate |
Fit to image treats one image pixel as one PDF point, which is 1/72 of an inch. A 4032 × 3024 photo therefore becomes a page about 56 × 42 inches. That looks perfectly normal in a PDF viewer, which fits the page to the window, but printers will scale it down to the paper. If the PDF is going to be printed or submitted as a document, choose a paper size instead.
Many home printers cannot print right to the edge of the paper. With no margin on a paper size, the outer few millimetres of each image may be cut off when printed.
How the size limit works
With Limit PDF size off, every page is encoded at the Quality you set, 88 percent by default, and the file is as large as that makes it.
With the limit on, the tool first sets aside a small allowance for the PDF structure itself, then divides the rest of the budget evenly between the pages. Each page is compressed to fit its share, lowering JPEG quality first and shrinking the image dimensions only if quality alone is not enough. Pages that need less than their share, such as a mostly blank page, leave bytes unused; those are handed to the pages that hit their limit, so detailed pages get more room. If the assembled file is still over the target, the whole process repeats with a smaller budget, up to four times.
If the target cannot be met at all, for example 50 pages in 100 KB, the PDF is still created and a note says the target was missed. Ready-made pages for common limits from 20 KB up to 5 MB set the target for you.
Worked example: ten phone photos into one A4 PDF
Say you photographed a ten-page signed contract with your phone. Each photo is 4032 × 3024 pixels and a few megabytes, and the recipient's email accepts attachments up to about 2 MB.
Drop all ten photos, drag them into page order, and use Edit to crop each one to the paper and rotate any that are sideways. Choose A4, leave Orientation on Auto, and keep the Small margin. Because the cropped pages are taller than they are wide, Auto keeps every page in portrait.
Turn on Limit PDF size and enter 2 MB. After the structure allowance, each page starts with a budget of a little over 200 KB. For a page of printed text, a JPEG of that size is comfortably readable on screen and in print. A page with a large signature or a stamp may hit its budget while a half-empty last page leaves some over, and the spare bytes are passed to the busier pages.
The result is one PDF of ten A4 pages just under 2 MB. If you need it smaller still, a 1 MB target halves the budget per page; check that the smallest print is still legible before sending.
Troubleshooting
- A page is sideways: Auto orientation turns the page, not the image. Rotate the image itself with Edit before creating the PDF.
- Text looks blurry after using the size limit: the budget per page was too small for the image. Raise the target, crop away empty space so the bytes go to the text, or split the document into two PDFs.
- White bands around a photo: the image shape does not match the paper. Use Fit to image with no margin for edge-to-edge pages, or crop the photo to the paper's proportions.
- Sharp screenshots show fuzzy edges around text: every page is stored as JPEG, which softens hard edges at lower quality. Raise Quality to 95 percent or more for screenshots and diagrams.
- The text cannot be searched or selected: the pages are images. To make a scan searchable, run each image through Image to Text (OCR) and download its searchable PDF.
- The browser slows down with many large photos: pages are encoded one at a time, but very large photos still need a lot of memory each. On a phone, crop the photos first or build the PDF in smaller parts.
- A transparent logo has a white background in the PDF: this is expected, because every page is a JPEG with a white backdrop.
Limits and what this tool does not do
The free plan puts up to 50 images into one PDF, with each file up to 200 MB; Pro allows 500 images and 1 GB per file. The tool creates new PDFs from images. It does not merge existing PDF files or edit pages inside them. To shrink a PDF you already have, use Compress PDF; to turn PDF pages back into images, use PDF to Image.
How this compares with upload-based converters
Online converters usually upload your images, build the PDF on a server and send you a download link. The result is similar, but your scans of contracts, IDs, payslips or medical letters spend time on someone else's server, often with a waiting queue or a daily limit on free files.
Here the PDF is built in your browser. Nothing is uploaded and there is no account. There is no model to download for this tool, so it works as soon as the page has loaded, and with Pro the installed app builds PDFs offline too. The trade-off is that a very large batch is limited by your own device's memory rather than a server's.