Photographing a printed form or saving screenshots is easy. Sending them to a client or government office in a single, properly ordered PDF is what people actually need. Image-to-PDF conversion is one of the most common requests we see, and getting it right takes more than just "pick a tool."
Why bundle images into a PDF at all
Most workflows that ask for "documents" really mean "PDF." A folder of .jpg files is awkward — recipients have to open each one, the order is fragile, and email systems may treat them as suspicious bulk attachments. A single PDF:
- Keeps pages in a fixed order.
- Lets you add a title page, signature, or watermark.
- Compresses better than the equivalent set of standalone images, especially when you choose the right options.
- Is universally accepted — every passport office, school portal, and HR system takes a PDF.
Method 1: Browser tool (drag, drop, done)
The shortest path is a browser-based image-to-PDF converter. Drop your JPGs and PNGs onto the page, drag to reorder, choose page size, and download. Docento.app processes everything locally on your device, which matters when the images contain ID documents, signatures, or anything else you would not normally upload.
Things to set before you export:
- Page size (A4 or Letter for most cases — pick Letter for US destinations).
- Orientation (auto usually works; force portrait if you have a mix and want consistent margins).
- Margin (a small margin looks more professional than full-bleed images).
- Fit mode (fit-to-page handles tall and wide photos gracefully; fill crops them — usually not what you want).
Method 2: Built-in OS tools
You don't always need a separate app:
- macOS Preview: open all the images in Preview, drag them into the desired order in the sidebar, then File → Export as PDF (or print to PDF if you want all pages combined).
- Windows Photos / File Explorer: select the images, right-click, and choose Print, then pick "Microsoft Print to PDF" as the printer. The print dialog lets you set layout and order.
- iOS / iPadOS Photos: select images, tap Share, then "Print," pinch-to-zoom on the print preview, and tap Share again to save as PDF.
- Android: most file managers and gallery apps now have a "Save as PDF" option in their share menu.
These cost nothing, are private, and work for most everyday cases.
Method 3: Microsoft Word or Google Docs
For documents that mix images with a few captions, dropping the JPGs into a Word or Google Doc and exporting to PDF is faster than fighting with image-to-PDF settings. You get text alongside images and can reuse the document later. See our Word to PDF guide for export tips.
Method 4: Scripted conversion for many files
If you convert images to PDFs every week (insurance claims, expense reports, school assignments), a small script saves hours:
img2pdf(Python tool) preserves the original JPG bytes inside the PDF, meaning zero quality loss and small file size.- ImageMagick:
magick *.jpg out.pdf— easy but recompresses, often making the PDF larger than the originals combined. - For very large batches, see our batch processing guide.
Quality and file size: the trade-off nobody explains
JPGs are already compressed. PNGs are lossless. When you wrap them into a PDF you can either:
- Embed as-is — same quality, same approximate file size as the originals combined.
- Recompress — smaller file, slight quality loss. Worth it for email when the originals are 12 MP photos of a one-page form.
For text-heavy images (a screenshot of a contract), PNG-as-is or modest JPG quality (~85) is the sweet spot. For photos, JPG quality 70-80 keeps file size down without visible artefacts.
Common mistakes
- Wrong rotation. Phone photos store rotation as metadata; some converters ignore it and your form ends up sideways. Pre-rotate the JPGs or use a converter that respects EXIF orientation.
- Mixed page sizes. A folder of phone photos taken in both orientations becomes a PDF with alternating tall and wide pages. Force a single size at export.
- Huge files from tiny images. If a 200 KB JPG becomes a 4 MB PDF page, the converter is upscaling it. Disable that behaviour or pick a different tool.
- Forgotten metadata. Phone photos include GPS coordinates. Strip image metadata before bundling, or strip metadata from the resulting PDF.
Conclusion
For one-off conversions, your operating system already does the job. For ordered, multi-image bundles where layout matters, a browser tool is faster and more flexible. Docento.app does this entirely on your device. For ongoing work, invest a few minutes in img2pdf and never think about the problem again.