Diplomas, certificates, receipts, signed forms, ID copies: many application portals want all of them as a single PDF, often with a size limit. You do not need a scanner. A phone camera and a few minutes of care are enough to produce a PDF that is easy to read and easy to upload.
Taking good photos of documents
The quality of the PDF is decided when you take the photos. No setting later can rescue a blurry or shadowed page.
- Light. Daylight from a window is ideal. Avoid the flash, which creates a bright glare spot, and make sure your own shadow and the phone's shadow do not fall on the page.
- Flat. Lay the document on a table. Weigh down curled corners, or press a folded page flat. Curved pages make lines of text bend.
- Straight. Hold the phone directly above the page, parallel to it. Shooting at an angle turns a rectangle into a trapezoid and makes the far edge smaller.
- Contrast. A dark table under white paper makes the edges easy to see and easy to crop.
- Focus. Tap the screen on the text to focus, hold still, and zoom into the photo afterwards to check that small print is readable.
- Fill the frame. Get close enough that the page fills most of the picture, but keep all four edges visible.
Many phones have a built-in document scanner, for example in Apple's Notes and Files apps or in the Google Drive app. These straighten pages automatically. If you use one and export images, you can still combine them as described below.
Preparing the images
A few quick fixes before combining make a big difference.
- Crop the background away with the crop tool.
- Rotate sideways or upside-down pages with the rotate tool.
- Improve readability with the black and white tool. Its threshold effect turns a page into pure black and white, which works well for typed text and signatures. For colored stamps or photos on a document, use grayscale or keep the color.
Combining the photos
The image to PDF tool puts one image on each page, in list order, and creates a single PDF.
- Open the tool and add all your images. JPG, PNG, WebP and HEIC are accepted, so iPhone photos do not need converting first.
- Check the order. Use the up and down buttons to move pages, and remove any you do not need.
- Choose the page size: fit to image, A4 or US Letter.
- Choose the orientation: auto, portrait or landscape. Auto lets the shape of your images decide.
- Choose the margin: none, small (10 mm) or large (20 mm).
- Set the image quality. The images are stored as JPEG inside the PDF, at quality 85 by default.
- Create and download the PDF, then open it to check every page.
Images are scaled to fit the page without cropping and are centered, so nothing gets cut off. Everything happens in your browser, which matters for documents with ID numbers and signatures: the files are not uploaded anywhere.
A4, Letter or fit to image?
| Page size | What you get | Best for |
|---|---|---|
| A4 | Every page is 210 x 297 mm | Official documents and anything that might be printed, in most of the world |
| US Letter | Every page is 8.5 x 11 in | The same, for the United States and Canada |
| Fit to image | Each page has the exact shape of its photo | Viewing on screen, mixed shapes such as receipts |
For applications, A4 or Letter is usually the better choice. All pages have the same size, the document looks orderly, and it prints correctly. A small margin also helps printers that cannot print right up to the edge. Fit to image avoids white borders, but pages of different shapes can look untidy and print at unpredictable sizes.
Keeping the PDF small
A PDF made from photos is roughly as large as the images inside it. A few multi-megabyte phone photos quickly add up to a PDF that is too large for an upload form.
Reduce the pixels. A page does not need 12 megapixels. For reference, a full A4 page needs 1240 x 1754 pixels at 150 DPI, 1654 x 2339 at 200 DPI and 2480 x 3508 at 300 DPI. Typed text is usually readable at 150 to 200 DPI; very small print may need more. The image resizer can set the longest side of every photo in one go, for example to 2000 pixels.
Lower the quality setting. In the image to PDF tool, a quality of 70 to 75 is often plenty for text documents.
Use black and white for text-only pages. Without the uneven paper tone and color noise, such pages often compress better.
Plan a budget per page. If the limit is 2 MB and you have five pages, each page can use about 400 KB, since 2 MB is 2000 or 2048 KB depending on how the form counts. Aim for around 350 KB per page to leave room. The compress to target size tool can bring each image under such a budget before you combine them. Because the PDF tool stores images as JPEG at the quality you choose, check the final PDF size and adjust if needed.
The guide to reducing file size explains the KB versus bytes question and the order of steps in more detail.
Turning PDF pages back into images
Sometimes you need the opposite: a form wants a JPG of a document you only have as a PDF, or you want to share one page as an image. The PDF to JPG tool renders every page and shows thumbnails.
- Open the tool and add one PDF. Password-protected PDFs are not supported.
- Choose JPG or PNG output.
- Choose the resolution: 72, 150 or 300 DPI. An A4 page becomes about 595 x 842 pixels at 72 DPI, 1240 x 1754 at 150 DPI and 2480 x 3508 at 300 DPI.
- Download single pages, or all pages as a ZIP.
The PDF renderer is downloaded into your browser the first time you use the tool. Large PDFs at 300 DPI need a lot of memory, so the tool renders pages one after another.
More background is on the PDF format page.
Frequently asked questions
Can I combine iPhone HEIC photos directly?
Yes. The image to PDF tool accepts HEIC files along with JPG, PNG and WebP, so you can add them without converting first.
Will the text in the PDF be searchable?
No. The PDF contains photos of your pages, not text. You can read it, but you cannot select or search the words. For most application uploads that is fine.
Why is my PDF so large?
Usually because the photos are at full camera resolution. Reduce the pixel dimensions, lower the quality setting, or use black and white for text pages, then create the PDF again.
Which page size should I choose?
A4 in most countries, US Letter in the United States and Canada. Use fit to image only when the PDF is meant for screen viewing.
