PDF

PDF to JPG vs PDF to PNG: Which to Choose (2026 Decision Guide)

Quick decision guide on whether to convert PDF to JPG or PNG. Resolution, quality, file size, transparency, every trade-off explained with real benchmarks.

DuneTools · · 7 min read

If you’ve ever converted a PDF to images, you’ve faced the choice: JPG or PNG? Both work. Both are universal. But picking the wrong one means either fuzzy text edges or files 4× bigger than necessary. This guide gives you a clean rule and the trade-offs behind it.

3–5×PNG vs JPG file size
2Decision factors
150DPI for screen viewing
~2sPer page conversion

The 5-second answer

Pick JPG when…

  • Page contains photos or color gradients
  • It's a scanned document (mostly bitmap content)
  • You'll send by email (file size matters)
  • You won't zoom past 200%
  • You don't need transparency

Pick PNG when…

  • Page is mostly text (sharp edges critical)
  • It's a diagram, chart, or screenshot
  • You'll re-edit or zoom heavily
  • You need transparency (rare for PDFs)
  • File size doesn't matter

If you’re not sure, default to JPG at quality 90, 150 DPI, works for 80% of cases.

What’s actually different

JPG (JPEG) and PNG are both lossless containers in the sense that “what gets saved” is what was rendered, but JPG applies lossy compression to the pixel data. PNG uses lossless compression, every pixel is preserved exactly.

PropertyJPGPNG
Compression typeLossy (DCT-based)Lossless (DEFLATE)
Best forPhotos, gradients, natural scenesText, line art, diagrams, screenshots
Max colors16.7M (24-bit)16.7M (24-bit) or more
TransparencyNoYes (alpha channel)
File size (A4 @ 150 DPI)~150–250 KB~600 KB – 1.5 MB
Quality knob1–100 (use 85–95)None (always perfect)
Re-edit cyclesEach save loses qualityInfinite (lossless)
Browser supportUniversal (1992)Universal (1996)

The text-edge problem

JPG's lossy compression operates in 8×8 pixel blocks (DCT). On smooth photo content this is invisible. On sharp text edges it produces "ringing" artefacts, faint halos around letters. PNG has no blocks, so text stays razor-sharp at any zoom level.

Real benchmarks: same page, both formats

Rendering a typical A4 page at 150 DPI (1240 × 1754 pixels):

Page contentJPG @ 90PNGRatio
Pure text (legal contract)195 KB580 KB1:3
Scientific paper (mixed text + figures)280 KB1.1 MB1:4
Magazine spread (photo-heavy)410 KB2.4 MB1:6
Engineering diagram (CAD lines)240 KB460 KB1:2
Screenshot (UI mockup)320 KB890 KB1:3

For a 50-page PDF, that’s the difference between a 12 MB attachment (JPG) and a 38 MB ZIP (PNG), Gmail’s 25 MB limit kills the PNG option entirely.

Resolution (DPI) explained

DPI = dots per inch = how many pixels each inch of the original PDF gets rendered into. Higher DPI = sharper output but bigger files.

DPIUse caseA4 pixel dimensionsJPG sizeQuality
72Email previews, thumbnails595 × 842~50 KBLow, text fuzzy
96Web embeds, casual viewing794 × 1123~80 KBAcceptable
150Standard screen viewing1240 × 1754~250 KBGood, sharp text
200Mobile zoom, basic printing1654 × 2339~450 KBExcellent
300Print, archival, heavy zoom2480 × 3508~900 KBPrint-grade
600+Forensic / scanning4960 × 7016~3 MBOverkill for most

The 150 DPI sweet spot

For 90% of digital use cases, 150 DPI is the right answer. It looks crisp on Retina displays at 100% zoom, files stay under 500 KB per page, and you can zoom to ~200% before pixelation appears. Only push to 200–300 DPI when you'll print or zoom heavily.

When to pick JPG

JPG wins when: (a) the page is photo-heavy or visually rich, (b) you’re sharing/emailing/uploading where size matters, (c) the user will view at normal zoom levels. Practical examples:

  • Scanned receipts and invoices → JPG. Photos of paper, text recognition still works.
  • Real estate photos in a brochure PDF → JPG. Photo content, large file otherwise.
  • Magazine pages → JPG. Photo-heavy, JPG built for this.
  • Social media uploads → JPG. Platforms re-compress anyway.
  • Email attachments → JPG. 4× smaller fits Gmail 25 MB limit.

When to pick PNG

PNG wins when: (a) the page has lots of fine text/lines, (b) sharp pixel edges matter, (c) the user might zoom in heavily, (d) file size is irrelevant. Examples:

  • Screenshots of UIs → PNG. Single-pixel borders, sharp text.
  • Engineering or CAD diagrams → PNG. Lines must be crisp.
  • Code snippets / terminal output → PNG. Monospace fonts shrink readably.
  • Charts and graphs → PNG. Anti-aliasing on edges renders better.
  • Pages you’ll re-edit → PNG. No quality loss on re-save.

How to convert without losing quality

The rendering engine matters as much as the format choice. Browser-based PDF→image converters (using PDF.js + canvas) are nearly indistinguishable from desktop tools, same pixels, same quality.

  1. Open PDF to JPG (or pick PNG mode if your content matches the PNG list above).
  2. Drop your PDF, it never uploads, processing happens in your browser via WASM.
  3. Pick DPI: 150 for screen, 200 for print, 300 for archival.
  4. For JPG: set quality 85–95. For PNG: no quality knob, always lossless.
  5. Download as a ZIP if multi-page, or single image if 1 page.

Avoiding the "scanned look"

If your output looks fuzzy or scanned, you probably picked too low a DPI. Bump from 96 → 150, almost always solves it. Bumping JPG quality from 80 → 95 helps less than DPI does.

Summary

Your situationFormatDPIQuality
Email scanned receiptJPG15085
Embed page in blog postJPG15090
Save magazine spreadJPG20092
Document UI screenshotPNG150n/a
Save engineering diagramPNG200n/a
Archive entire scanned bookJPG20095
Print previewPNG200n/a
Print readyJPG or PNG30095

When in doubt, JPG at 150 DPI quality 90. Use PNG when text/lines matter or files need to survive future editing without degradation.