How to Convert JPG and PNG Images to PDF

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Turn photos, scanned pages and screenshots into a PDF, combine them with existing PDFs, and understand how page size and file size are decided.

Why convert images to PDF

Images are convenient to capture but awkward to share as a set. A folder of twelve receipt photos, a series of whiteboard pictures, or several screenshots documenting a bug are much easier to send, print and archive as one PDF with a fixed order. Many forms and portals also only accept PDF uploads, even for documents you photographed with your phone.

ModiPDF can add JPG and PNG images as pages, either on their own or mixed with pages from existing PDFs. The conversion runs locally in your browser, so your photos are not uploaded anywhere.

Step-by-step: images to PDF

  1. Gather the images in one folder and, if possible, rename them so they sort in the order you want (for example 01-receipt.jpg, 02-receipt.jpg).
  2. On the ModiPDF home page, drop the images onto the upload area or click it and select them. Each image becomes one page.
  3. In the editor, check the order in the Pages panel and drag thumbnails to rearrange them if needed.
  4. If a photo appears sideways, hover over its thumbnail and click the rotate icon until it reads correctly.
  5. Use the + button in the Pages panel to add more images or existing PDF files to the same document.
  6. Enter a file name at the top left and click Export to download the PDF.

How page size is decided

Each image becomes a page whose dimensions match the image's pixel dimensions, and the image fills the page with no added margins. That keeps the full picture without cropping, but it also means pages from different images can have different sizes. A tall phone screenshot produces a tall, narrow page; a large camera photo produces a very large page.

This is usually fine for reading on screen. When printing, most PDF viewers offer a 'fit to page' or 'shrink to fit' option that scales each page to the paper size. If you need uniform page sizes, crop or resize your images to the same proportions before adding them.

Image quality and file size

ModiPDF embeds your images as they are, without recompressing them. Quality is preserved, but the PDF will be about as large as the images combined. ModiPDF does not include a compression feature, so if the final file must stay under an upload limit, reduce the images before adding them: lower the resolution in your photo app, or save photos as JPG rather than PNG, which is usually much smaller for photographs.

PNG remains the better choice for screenshots, diagrams and text-heavy images, because it keeps sharp edges without compression artefacts.

Supported formats

For reliable results, use JPG (JPEG) or PNG files. Other image formats, such as HEIC photos from some phones or WebP images saved from websites, may display in the editor but cannot be embedded in the exported PDF. Convert them to JPG or PNG first; most phones and operating systems can do this when exporting or sharing a photo.

Tips

  • Photograph documents in good, even light and fill the frame with the page; it improves readability far more than any later adjustment.
  • Crop away table surfaces and backgrounds before converting so the page contains only the document.
  • Keep related images together in one export rather than creating many single-page PDFs.
  • If you want to add text or a signature on top of a photographed page, export the images to PDF first, then open that new PDF in ModiPDF and add your annotations. Annotations are saved onto pages that come from PDF files.

Common mistakes to avoid

  • Using unsupported formats such as HEIC or WebP and finding pages missing from the export.
  • Adding very high-resolution photos and producing a file too large to email.
  • Forgetting to check orientation. Phone photos sometimes carry orientation information that viewers interpret differently, so confirm each page in the exported file.
  • Relying on the original file names for order without checking. Always review the Pages panel before exporting.

Try it in ModiPDF

Free to use, no account needed, and your files stay in your browser.

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