2026-05-12 · 8 min read
PDF vs JPG: When to Use Each Format
People treat PDF and JPG as interchangeable ways to hand someone a document, but they were built for opposite jobs. PDF is a container for structured pages with text, vectors, and metadata. JPG is a compressed bitmap of pixels, and only pixels. Pick the wrong one and you produce a 14 MB image of a one-page memo, or worse, a searchable contract that nobody can search anymore. Below is the practical comparison and the rule that decides almost every case.
What each format actually is
PDF (Portable Document Format) is a page-description language. A PDF stores text as text (with embedded fonts), shapes as vectors, and only embeds raster images where there are actual photos. It can hold metadata, hyperlinks, form fields, digital signatures, layers, and annotations. Each page renders identically on any device.
JPG (JPEG) is a lossy raster image format published in 1992. It stores pixels, compressed using discrete cosine transforms tuned for the way human vision handles brightness and colour. It’s superb at photographs and unsuited to anything with hard edges, fine text, or sharp colour transitions.
Side-by-side comparison
| JPG | ||
|---|---|---|
| Stores text | Yes (selectable, searchable) | No (just pixels of text) |
| Stores photos | Yes, can embed JPGs | Native |
| Multiple pages | Yes | No (one image) |
| File size for text | Small (kilobytes) | Large (megabytes) |
| File size for photos | Larger (PDF overhead) | Smallest available |
| Print fidelity | Excellent at any size | Pixelates if scaled up |
| Sharable on chat / social | Sometimes awkward | Native everywhere |
| Accessibility (screen readers) | Possible with tagging | None unless alt text |
| Digital signing | Industry standard | Not supported |
| Editing later | Possible | Effectively no (lossy) |
The simple rule
Use PDF for documents — anything that contains structured text, multiple pages, signatures, or that someone might want to print, search, or sign. Use JPG for photos — anything where the content is genuinely pixels: a photograph, a screenshot of an interface, an artwork, a meme. If you’re unsure: does it have selectable text? It’s a document. Use PDF.
File-size reality check
A common mistake: photographing a one-page receipt with your phone camera, sending the JPG. The phone produces a 4–8 MB high-resolution photo. The same content, scanned to PDF via the phone’s built-in document scanner (iOS Files app, Google Drive), is typically 80–200 KB — twenty to a hundred times smaller, with cropped and corrected geometry, real text where possible, and printable at any size.
The reverse mistake: exporting a magazine cover as a PDF when the recipient just wants to view the image on their phone. Now they need a PDF reader instead of their photo gallery. JPG would have worked fine.
Worked examples
- Restaurant receipt for expense claim → PDF. Scanner app on your phone produces a small, searchable, croppable file.
- Photo of a whiteboard from a meeting → JPG. It’s a photo of a whiteboard. The content is pixels.
- Multi-page contract → PDF. JPG can’t do multiple pages without bundling, has no signatures, can’t embed metadata.
- Single-page marketing poster you’ll post on Instagram → JPG. Native to social, smaller than the equivalent PDF for a heavily designed image.
- Photograph of an artwork for a portfolio → JPG, embedded in a PDF portfolio if you’re sending several.
- Screenshot of an error message for IT support→ JPG or PNG. Don’t make support open a PDF for one screenshot.
- Identity document for a bank → PDF. Most banks explicitly require PDF; many reject JPG uploads.
When the document is a JPG and they want a PDF
Common request: bank or government portal asks for a PDF, you have a photo. The fix is one click in most operating systems:
- Mac: open the JPG in Preview, File → Export as PDF.
- Windows: open the JPG, File → Print → choose “Microsoft Print to PDF”, save.
- iPhone / Android: open the photo in Files / Drive, share → Print → pinch-out to preview → share as PDF (iOS), or use the built-in scanner instead next time.
- Multiple JPGs into one PDF: our guide to combining multiple images into a PDF covers this in detail.
When the PDF is bloated with images
The other half of the equation: a PDF that’s huge because it embeds full-resolution photos. A 50 MB scanned report is almost always a PDF where each page is a 12-megapixel JPG when it could have been a 200 KB JPG at screen resolution. Compress with the right settings and the file shrinks 90% with no visible loss. See our guide to compressing a PDF for the specifics — the key knob is image DPI and JPG quality, both of which most compressors expose.
A note on JPG’s cousins (PNG, WEBP, HEIC)
JPG isn’t the only image format you might consider:
- PNG — lossless, supports transparency. Better for screenshots of UI, diagrams with text, and anything where compression artefacts would matter. Larger files.
- WEBP — modern, both lossy and lossless, smaller than JPG at similar quality. Good for the web; less universally supported as an attachment.
- HEIC — what your iPhone shoots by default. Smaller than JPG but many recipients can’t open it. Convert before sending.
For the question at hand — image vs document — the choice between JPG, PNG, WEBP, and HEIC is downstream of the choice between “an image format” and PDF.
For documents, prefer PDF over PDF/A-equivalent JPG bundles
Some workflows produce JPG-per-page bundles claiming to be documents. Avoid them: no text layer, no search, no accessibility, no metadata, no signing, larger than PDF. If you receive a folder of numbered JPGs that should have been a document, combine them into a PDF with our images-to-PDF guide and run OCR if you need searchable text afterwards.
Quick decision tree
- Has selectable text or multiple pages? → PDF.
- Will be signed or printed? → PDF.
- Going to a bank, government, or HR system? → PDF.
- Is it a photograph or screenshot? → JPG.
- Going to social media or chat? → JPG.
- Is it a UI screenshot with text? → PNG, not JPG.
The same logic applies for the related “PDF vs DOCX” question — see our PDF vs DOCX comparison for that. And if your PDF is too big because of embedded images, the compression guide will trim it without sacrificing readability.