How to add scanned images to an existing PDF

PDF pages hold images perfectly well, but a merge tool works on PDFs, not on a mixed pile of formats. The reliable pattern is two steps: normalise everything to PDF, then combine. Doing it in that order also gives you a chance to fix orientation and page size before anything is locked into a page tree.

Step 1: turn the images into PDF pages

1. Gather the images in one folderRename them so they sort in the order you want: 01.jpg, 02.jpg, and so on. Zero-padding matters, because 10.jpg sorts before 2.jpg otherwise.
2. Open the converterGo to JPG to PDF and drop the whole folder selection in at once.
3. Pick a page sizeUnder Page size, choose A4, Letter or Same as image. Then choose Fit inside margins, Fill page or Original size. Fit inside margins keeps the whole picture visible; Fill page can crop its edges.
4. Check image orientationThe converter does not offer an EXIF auto-rotate switch. Open the output and check each page; if one is sideways, rotate it with Organize Pages or Rotate PDF.
5. ConvertYou get either one PDF per image or a single multi-page PDF, depending on the option chosen. For merging, one multi-page PDF is fewer things to drag.

HEIC: why iPhone photos need a moment

The JPG to PDF tool accepts JPG, PNG and WebP, not HEIC. Convert HEIC images with HEIC to JPG first, then add the resulting JPG files. The conversion changes the image format, so check the converted file before assembling a document.

If you would rather avoid the issue entirely, change the camera setting: Settings → Camera → Formats → Most Compatible makes the iPhone shoot JPEG instead. And if you AirDrop photos to a Mac, macOS converts on the fly, which is why the same photo is sometimes HEIC and sometimes JPEG depending on how it arrived.

Step 2: merge everything

With every input now a PDF, open Merge PDF, add the files in the intended sequence, check the order shown, and run the merge. A typical expense claim might contain a cover letter, receipt pages and a statement. Review the output before sending it.

Getting the resolution right

This is where image-to-PDF goes wrong. An image has pixels; a PDF page has physical dimensions. The relationship between them is DPI, and choosing badly gives you either a blurry printout or a 90 MB file.

Image pixel dimensions affect how sharp a page looks when printed. The JPG to PDF tool does not provide a DPI or image-resampling setting, so prepare a smaller copy in an image editor if you need to reduce resolution before conversion. Keep the original, and inspect a test page at the intended print size.

The receipt problem, worked through

The output size depends on the number and dimensions of the source images. Email and workplace upload limits vary, so check the current limit for the account or portal you are using. If the PDF is too large, make a backup and try the options below:

1. Resize or convert copies of the source photos in an image editor before making the PDF. This JPG to PDF tool does not offer a DPI or grayscale option, so check that small receipt text remains readable.
2. Use the browser's print or image tools only if their output is suitable; compare the result with the original before discarding anything.
3. Try Compress PDF on a copy. Medium and Strong turn pages into images, which can reduce size but removes selectable text and may lower detail.

Making the result searchable

A PDF made from photos contains no text, only pictures of text. Ctrl+F finds nothing, and neither will your accounting software or your operating system search index. Running OCR adds an invisible text layer under the image: the page looks identical, but the amounts, dates and vendor names become searchable and copyable. For a receipts archive this is the difference between a folder you use and a folder you forget.

A note on quality loss

Placing a JPEG into a PDF is lossless: the original JPEG bytes are embedded as-is, so the page is exactly as good as the file you started with. Quality is only lost if you downsample during conversion or compress afterwards, both of which are choices you control. PNG behaves differently, since PDF re-encodes it, but the result is still visually identical for screenshots and diagrams.

Frequently asked questions