If you're not technical: use the free online tool
If you're not a technical person and you're looking for a free way to turn JPG or PNG images into a PDF, use my online image to PDF converter. Add your pictures, arrange them, choose a page size and download one PDF. No installation or account is needed.
It works well for collecting photographed pages, receipts or screenshots into one attachment, with one image per page.
If you're technical, I'll explain how to calculate the image placement and build those pages after the steps.
How to combine JPG images into a PDF
- Open Image to PDF and choose your images.
- Use Add images if you need to include more.
- Arrange them with the up and down arrows.
- Choose A4, US Letter or Original page size.
- Set the margin and choose landscape if appropriate.
- Select Generate PDF, inspect the preview and choose Download PDF.
The tool accepts up to 12 images per PDF, with a combined input limit of 60 MB.
Before generating, check the sequence against the document itself. Camera file names do not always make the intended reading order obvious.
If you're technical: how it works
If you're technical, the basic workflow is to decode each image, embed it in a new PDF, and draw it on its own page. My implementation uses pdf-lib and fits each image inside the chosen margins.
The fit calculation is straightforward. Given the source image's pixel dimensions and the PDF page's dimensions in points:
const availableWidth = pageWidth - 2 * margin; const availableHeight = pageHeight - 2 * margin; const scale = Math.min( availableWidth / imageWidth, availableHeight / imageHeight ); const width = imageWidth * scale; const height = imageHeight * scale; const x = (pageWidth - width) / 2; const y = (pageHeight - height) / 2; This is the placement calculation, not a complete converter. Pass the resulting x, y, width and height to the PDF image-drawing step. Taking the smaller scale factor keeps the whole image inside the page without cropping or stretching it.
Validate dimensions and margins first. Image decoding, memory limits, orientation and download handling are additional parts of a usable browser tool.
A4, Letter or Original: which should you choose?
Use A4 or US Letter when the document is intended for printing on that paper size.
Use Original when you want each PDF page to match its image's dimensions, which can suit screenshots and documents meant only for screens.
For a wide image, landscape can make better use of a standard sheet. The tool fits the image within the available page area while keeping its proportions; it does not crop the image to fill the page.
That means a differently shaped picture may have empty space beside it. Preserving all the content is usually more useful than filling every corner.
How to remove the white border
Choose Original page size and set the margin to 0 if you want the page boundary to follow the image without an added margin.
This only removes the margin added by the converter. If your photo already includes a desk, a wall or a white border, that is part of the image. Crop the photo first if you want it removed.
The converter packages the pictures; it does not automatically straighten a photographed sheet or recognize the text inside it.
Why is the PDF larger than the photos?
Turning photos into a PDF does not automatically compress them.
This tool embeds images losslessly, so a PDF made from compressed JPG photos can be larger than the source images. If an upload limit matters, resize large photos first or use the PDF compressor on the finished document.
Always check small text after any size reduction. A smaller file is only useful if the recipient can still read it.
One file is easier to check and send
The PDF is generated in your browser, without uploading the photos for conversion.
Open the downloaded copy once before sharing it. Confirm that no page is missing, every image faces the right direction, and the final page order makes sense.
What do you turn into PDFs most often: receipts, phone scans or screenshots?
