Resolution as a number, not a guess. Every other converter offers “low, medium, high” without saying what that means, so anyone who needs 300 DPI for print has to convert and check. Here the DPI is stated and so are the pixels it produces. Nothing is uploaded, and there is no page or file limit.
PDF to Images
LocalWhat DPI actually means
Dots per inch decides how many pixels each printed inch becomes. A PDF page is measured in points — 72 to the inch — so the multiplier is simply the DPI divided by 72. On an A4 page:
| DPI | Pixels | One page as PNG | Right for |
|---|---|---|---|
| 72 | 595 × 842 | ~1.5 MB | Email, a web thumbnail, a quick look. Text is legible but not sharp |
| 150 | 1240 × 1754 | ~6.5 MB | Everyday printing and most screens. The sensible default |
| 300 | 2480 × 3508 | ~26 MB | Professional print, anything going to a press, fine detail |
| 600 | 4961 × 7016 | ~104 MB | Archival scanning and OCR input. Rarely worth it otherwise |
Which format
| Format | Size, one A4 at 150 DPI | Lossless | Choose it for |
|---|---|---|---|
| PNG | ~6.5 MB | Yes | Text, diagrams, screenshots, anything with sharp edges. Supports transparency |
| JPEG | ~0.5 MB | No | Photographs and scans. Universally supported, but it smudges text edges |
| WebP | ~0.35 MB | Optional | The best of both, if everything that will open it is modern. Supports transparency |
PNG for documents, JPEG for photographs. The difference is not subjective: JPEG works by discarding detail the eye is bad at noticing in continuous-tone images, and the sharp black-on-white transitions of text are exactly what it handles worst. A page of text at JPEG 85 shows visible haze around the letters; the same page as PNG does not, at ten times the size.
Transparent backgrounds
A PDF page usually has no background of its own — the white you see is the paper the viewer draws underneath. Rendering with a transparent background keeps that, which matters when the result is going somewhere that already has a background:
| Use | Why transparency helps |
|---|---|
| A logo or diagram | Sits on a coloured slide or page without a white box around it |
| Presentation slides | Layers over a template background |
| Overlays and stamps | Only the marks land, not a white rectangle |
| Ordinary documents | It does not — use white. Transparent text on a dark viewer becomes unreadable |
JPEG cannot store transparency at all; choosing it forces a white background. PNG and WebP both can.
Why a ZIP, and why no library for it
A twenty-page document produces twenty images. Browsers handle that badly — downloads get blocked after the first few, each one prompts, and the results scatter across a folder.
Building the archive turns out not to need a dependency. A stored, uncompressed ZIP is four small structures and a checksum per entry. PNG, JPEG and WebP are already compressed, so deflating them again would save a percent or two for a noticeable delay and 95 KB of extra code. Storing them is simpler, faster, and for this content barely larger.
What the resolution costs
File size grows with the square of the resolution, so the setting matters far more than it appears:
| DPI | An A4 page becomes | Roughly | Suits |
|---|---|---|---|
| 72 | 595 × 842 pixels | 0.2 MB | Thumbnails, previews |
| 150 | 1,240 × 1,754 | 0.9 MB | On-screen reading, slides |
| 300 | 2,480 × 3,508 | 3.7 MB | Printing. The usual default |
| 600 | 4,961 × 7,016 | 14.9 MB | Archival scanning, fine detail |
Going from 150 to 600 dpi multiplies the size by sixteen, not four. Doubling the resolution doubles both dimensions, so the pixel count quadruples each time. A twenty-page document at 600 dpi is close to 300 MB before compression — and the extra detail is invisible unless you are printing at larger than original size.
Which format, and when the answer is neither
| Format | Best for | Note |
|---|---|---|
| PNG | Text, diagrams, line art | Lossless, so letter edges stay sharp. Supports transparency. The right default for documents |
| JPEG | Photographic pages | Much smaller for photographs, and visibly poor on text — compression artefacts cluster around hard edges |
| WebP | Web publishing | Smaller than both at similar quality. Not accepted by every application that takes images |
| Neither — keep the PDF | Sharing a document | If the recipient needs to read, search or quote it, images are worse in every respect including size |
What one A4 page weighs at each setting
| DPI | Pixel dimensions | PNG, roughly | Suits |
|---|---|---|---|
| 72 | 595 × 842 | 0.4 MB | Thumbnails and previews only |
| 96 | 794 × 1,122 | 0.6 MB | Screen display, web embedding |
| 150 | 1,241 × 1,754 | 1.6 MB | The usual choice. Readable on screen, acceptable in print |
| 300 | 2,481 × 3,507 | 6.2 MB | Print quality. The standard for anything going to paper |
| 600 | 4,962 × 7,014 | 25 MB | Archival and OCR of small type. Rarely needed otherwise |
Doubling the DPI quadruples the pixel count and roughly quadruples the file. A twenty-page document at 600 dpi is around half a gigabyte of PNGs; the same document at 150 is under 35 MB and looks identical on a screen. Choose the resolution for where the images will actually be looked at.
When images are the wrong answer
| What you want | Images? | Better |
|---|---|---|
| A thumbnail or preview | Yes | This is exactly the job |
| Put a page in a slide or document | Yes | An image embeds cleanly anywhere |
| Extract one photograph | No | Rendering the page captures the whole layout. A PDF extraction tool pulls the embedded image at its original quality |
| Make a file smaller | No | Images are almost always larger than the text they replace |
| Stop someone copying the text | No | OCR defeats it in seconds, and you have broken accessibility for everyone else in exchange |
| Send fewer pages | No | Split the PDF instead. It keeps the text and the file stays small |
Common mistakes
Frequently asked questions
What DPI should I use?
150 for almost everything — it prints well and looks sharp on any screen. Use 300 when something is going to a press at full size, and 600 only for archival scanning or as OCR input. Doubling the DPI quadruples the file size, so 600 is sixteen times the weight of 150 for no visible gain on screen.
PNG or JPEG?
PNG for documents, JPEG for photographs. JPEG compresses by discarding detail the eye misses in continuous-tone images, and sharp black-on-white text is precisely what it handles worst — you get visible haze around the letters. PNG is around ten times larger and correct. WebP sits between the two if everything that will open the file is modern.
Can I convert just some pages?
Yes. Type ranges like 1-5, 8, 12- in the pages field. Most converters process the whole document whether you wanted page 7 or not. Note that the numbers are positions in the file, so a cover and two front-matter pages put the printed “page 1” at position 4.
Why is the file so large?
Because an image of a page holds a colour for every pixel, while the PDF held instructions for drawing it. A one-page PDF of text might be 40 KB; the same page as a 300 DPI PNG is 26 MB. Lower the DPI or switch to JPEG or WebP, and check the estimate above the button before converting.
Can I get transparent backgrounds?
Yes, with PNG or WebP. A PDF page usually has no background of its own — the white is drawn by the viewer — so rendering transparently gives you just the marks. That is what you want for a logo or a slide overlay, and not what you want for a document, where transparent text on a dark background becomes unreadable. JPEG cannot store transparency and will always be white.
Will the text be searchable?
No. Converting to images turns text into pixels, so searching, selecting and copying all stop working. If the words are what you want, use a text extractor instead — the PDF to Markdown tool pulls them out in your browser.
Is my file uploaded?
No. It is rendered by your browser and the images are written there too — the network panel in developer tools will show no request carrying your document. The only network request is for the rendering library, and it happens once.
Why do I get a ZIP?
Because twenty separate downloads is worse — browsers block or repeatedly prompt for them and scatter the results. A single page comes back as a plain image with no archive. The ZIP is built here rather than with a library: images are already compressed, so a stored archive costs nothing and saves 95 KB of code.
Is there a page or size limit?
No cap is imposed. The real ceiling is your own machine’s memory, which is why the estimate is shown first — a warning appears when the settings would produce more than a browser can comfortably hold.
Related tools
See the full list of Document Tools, or try:
- Images to PDF — the other direction, with correct rotation
- PDF to Markdown — the text rather than a picture of it
- Split PDF — several ranges in one pass
- Merge PDF — combine with page-level control
- Add Page Numbers to PDF — number the source before archiving it