Posting a document page on social media, dropping a diagram into a presentation, recovering a photo from a catalogue: you often need an image when all you have is a PDF. There are two different operations that must not be confused: turning a whole page into an image (rendering), or pulling out the images the PDF contains (extraction).
Rendering a page or extracting an image: the difference
| Convert to images | Extract images | |
|---|---|---|
| What you get | One image per page, as displayed (text, layout and pictures together). | The embedded photos and illustrations, one by one. |
| Resolution | The one you choose (up to 300 dpi). | Each image's original resolution: JPEGs come out byte for byte. |
| Text | Becomes pixels, not selectable. | Not concerned: only pictures come out. |
Converting pages to images step by step
- Leave “Pages” empty to convert everything, or type “1-3, 5, 8-”; you can also tap the thumbnails.
- Pick the resolution: 150 dpi suits screens and sharing; go up to 300 dpi to print or zoom. For JPG, the quality slider trades weight against sharpness.
- With PNG, tick “Transparent background” so empty areas are not painted white (useful to lift a logo or a diagram).
- Download the images one by one or, as soon as there are several pages, in a ZIP archive.
Which resolution, which format?
Resolution sets the number of pixels: an A4 page measures about 595 × 842 pixels at 72 dpi, 1,240 × 1,754 at 150 dpi and 2,480 × 3,508 at 300 dpi. Doubling the resolution therefore multiplies the pixel count by four, and the image's weight in proportion.
| Resolution | Dimensions (pixels) | Total pixels | Typical use |
|---|---|---|---|
| 72 dpi | 595 × 842 | ≈ 0.5 million | Thumbnail, preview. |
| 150 dpi | 1,240 × 1,754 | ≈ 2.2 million | Screen, social media, email. |
| 300 dpi | 2,480 × 3,508 | ≈ 8.7 million | Printing, zooming, small type. |
As for format, JPG suits photo-rich pages: it is much lighter. PNG suits text pages, diagrams and screenshots: it loses nothing and avoids the halos JPG adds around letters. For a page of pure text, PNG is often as light as JPG; for a photo page at 300 dpi, it can be several times heavier.
Extracting a PDF's images
The “Ignore small images” option hides bullets, rules and tiny icons that clutter the list (adjustable from 32 to 256 pixels). A PDF made only of text and vector drawings contains no image at all: the tool says so instead of inventing a result. A scanned document yields one big image per page.
Practical tips
- Convert only the pages you need. On a phone, a few pages at a time avoids saturating memory, especially as PNG at 300 dpi.
- Need the text, not a picture? Use a text extraction tool instead, or character recognition for a scan (see Extract text from an image or scanned PDF (OCR): a practical guide).
- For a light image to share, convert to JPG at 150 dpi with a quality of 75 to 85%, then shrink it further if needed (see Shrink an image's file size with no visible loss).
- For social media, adjust the dimensions afterwards (see Resize and crop an image for the web, Instagram or YouTube).
Common mistakes
- Choosing 300 dpi PNG for a whole 200-page book: the archive will be huge and the conversion slow.
- Expecting a transparent-background page from a JPG: JPG has none, empty areas are white.
- Extracting images from a scanned PDF and being surprised to receive whole pages: that is exactly what such a PDF contains.
- Using images extracted from a copyrighted document without permission.
Honest limits
- A huge page (blueprint, poster) is automatically scaled down to what your device's memory allows, and the tool tells you so.
- Rendering may differ very slightly from your usual PDF reader's for unusual fonts or effects.
- An extracted image is not always directly usable: some are fragments of an illustration sliced by the layout software.
Frequently asked questions
What is the best resolution for publishing online?
150 dpi suits most on-screen uses. Beyond that you make the image heavier with no visible gain, unless readers need to zoom.
Why does my image have a white background?
Because a PDF page is white by default. With PNG, tick “Transparent background” to keep empty areas transparent.
Can I convert a protected PDF?
Yes, if you know its password: type it into the tool, it stays on your device.
Do extracted images lose quality?
JPEGs come out identical to what was in the PDF. Others are saved as lossless PNG.
Is my PDF sent to a server?
No. Conversion is done by your browser; nothing is transmitted or kept.