How to Convert JPG to PDF Online for Free: Combine Images into One File

Converting JPG or PNG images into a single PDF file can be easily done using a free online tool. This method allows you to collect photographic pages, receipts, or screenshots all together, with each image appearing on its own page. No installation or account creation is required, making the process simple and straightforward.

To begin, visit the "Image to PDF" converter and select the images you want to include. You can add additional images using the "Add images" option if needed. Once your images are uploaded, arrange them using the up and down arrows to set the desired order. Choose the appropriate page size—A4, US Letter, or Original—based on your needs. Set the margins and decide if a landscape orientation is more suitable.

Click "Generate PDF" to preview your document. If everything looks correct, you can then download the final PDF file. The tool supports up to 12 images per PDF, with a combined input limit of 60 MB.

For those interested in how the process works under the hood, the conversion involves decoding each image, embedding it into a new PDF, and positioning it on its own page. My implementation uses the pdf-lib library to fit each image inside the chosen margins. The algorithm calculates the scaling factor based on the image's pixel dimensions and the PDF page's dimensions, ensuring the entire image fits without cropping or stretching.

The placement calculation determines the x and y coordinates for each image, keeping the image proportions intact.

When deciding on the page size, consider the intended use of the PDF. A4 or US Letter are good choices for documents meant for printing, while Original preserves the image dimensions, which can be useful for screenshots or other screen-based content. For wide images, selecting landscape orientation can make better use of the standard sheet size. Keep in mind that the tool fits the image within the available page area while maintaining its proportions, which may result in empty space around the image.

If you prefer a PDF with no white border, choose the Original page size and set the margin to 0. However, this will only remove the margin added by the converter; any existing white borders in the images will remain. The converter simply packages the images together; it does not perform any automatic straightening or text recognition.

Keep in mind that the resulting PDF may be larger than the original JPG or PNG files since the tool embeds the images losslessly, preserving all the quality. If file size is a concern, you can resize the images before uploading or use a separate PDF compressor on the finished document.

Before sharing the PDF, it is essential to review the document in your browser. Confirm that all pages are present, each image is correctly oriented, and the final page order makes logical sense. This final check ensures that the PDF accurately represents the original images and is ready for distribution.