A job portal wants your certificate as an image, not a document. A chat app shows a PDF as an attachment nobody taps, while a picture appears right in the conversation. A slide needs one page of a report pasted in. In each case the page has to stop being a PDF page and become an image file.
The conversion itself is simple. The decisions around it are where people go wrong: which resolution to render at, whether the output should be JPG or PNG, and what to do when the PDF is password-protected, very long or has a huge page. This guide goes through each one with exact pixel sizes, so you can pick settings once instead of converting three times.
TL;DR: Turning a PDF into images means rendering each page to pixels at a chosen resolution. PDF pages are measured in points, 72 to the inch, so the DPI you pick sets the pixel size directly: an A4 page is 1240 x 1754 pixels at 150 DPI and 2480 x 3508 at 300 DPI. Use 150 DPI for screens and forms, 300 for print, 72 for thumbnails. Pick JPG for photo-heavy pages and small files, PNG for text and line art. The PDF to JPG converter renders every page client-side, nothing uploaded, free, no signup; the PDF to PNG converter gives lossless pages.
What does converting a PDF to JPG do?
Converting a PDF to JPG draws each page onto a grid of pixels, the way a PDF reader draws it on your screen, and saves that grid as a JPEG image. One page becomes one image. A 12-page PDF gives 12 files.
A PDF page is not made of pixels to begin with. The format, standardized as ISO 32000-2, describes text as characters in a font, lines and shapes as vector paths, and photos as embedded images, all positioned on a page measured in points. Rendering replaces all of that with a fixed pixel grid. The consequences follow directly:
- Text becomes pixels. It can no longer be selected, searched or copied.
- Vector drawings lose their ability to scale. Zoom into the image and edges turn into visible pixels.
- Page size in inches turns into a pixel size, set by the resolution you choose.
The original PDF is not changed. Keep it for anything that needs searchable text or perfect print scaling, and use the images where images are required.
How does the Toolz converter render the pages?
Pages are rendered by pdf.js, Mozilla's open source PDF renderer, the same engine Firefox uses to show PDFs. It is downloaded only when you add the first PDF, and it runs inside the browser tab.
The converter starts as soon as a PDF is added. There is no Convert button: every page is rendered and encoded in turn, and changing the resolution or the quality renders the pages again with the new setting. You can add several PDFs at once, and each one gets its own row.
Each page's image is named after the PDF with the page number, zero-padded to the width of the page count so files sort in page order. A 12-page report.pdf gives report-page-01.jpg through report-page-12.jpg. A 9-page file uses a single digit, and a 100-page file uses three.
There are three ways to download:
| What you want | Where to click | What you get |
|---|---|---|
| One page | Show pages on the row, then that page's download icon | A single JPG, such as report-page-03.jpg |
| Every page of one PDF | The download icon on the PDF's row | A ZIP named after the PDF, such as report-jpg.zip |
| Every page of every PDF | Download All in the list header | converted-jpg.zip |
When several PDFs are in the list, Download All puts every page of every PDF into one ZIP. If two PDFs share a name, say two files both called scan.pdf from different folders, repeated names inside the ZIP get a number added, so no page overwrites another. To keep each document's pages together, download them row by row instead.
Before rendering anything, the converter opens the PDF and checks every page's size at the chosen resolution. A page that would be too large fails the file at once, with a message naming the page, instead of after minutes of work.
Which DPI should you choose?
Use 150 DPI for reading on screen, slides and most upload forms, 300 DPI for printing or for zooming into small print, and 72 DPI for thumbnails and quick previews. The converter offers exactly these three, with 150 as the default.
The arithmetic is short. PDF pages are measured in points, 72 to the inch, so the pixel size of a page is its size in points multiplied by DPI / 72. An A4 page is 595.28 by 841.89 points. At 150 DPI that is 595.28 x 150 / 72 = 1240 pixels wide and 841.89 x 150 / 72 = 1754 pixels tall, after rounding.
| Resolution | A4 page (210 x 297 mm) | US Letter page (8.5 x 11 in) | Use it for |
|---|---|---|---|
| 72 DPI | 595 x 842 px, 0.5 MP | 612 x 792 px, 0.48 MP | Thumbnails, chat previews, pages where small files matter most |
| 150 DPI (default) | 1240 x 1754 px, 2.17 MP | 1275 x 1650 px, 2.10 MP | Screens, slides, web pages, most upload forms |
| 300 DPI | 2480 x 3508 px, 8.70 MP | 2550 x 3300 px, 8.41 MP | Printing, fine print, drawings, cropping details |
Doubling the DPI doubles both sides of the image, so a 300 DPI page has four times the pixels of the same page at 150 DPI. File size grows with it, though not exactly fourfold, because how well a page compresses depends on what is on it.
A worked example: which setting fits the job?
Say a 12-page A4 report needs to go into a presentation, and one page must also be printed.
- A typical 1920 x 1080 screen is 1,080 pixels tall. An A4 page at 150 DPI is 1,754 pixels tall, so it already has more detail than a full-screen slide can show. 150 DPI is enough for the deck.
- For the printed page, 300 DPI gives 2480 x 3508 pixels, which fills an A4 sheet at the resolution print shops usually ask for.
- If a form says "image, maximum 1,000 pixels on the long side", 72 DPI gives 842 pixels on an A4 page and fits without resizing. 150 DPI would need resizing afterward.
Changing the setting re-renders the pages, so you can compare 150 and 300 on the same PDF without adding it twice.
Blurry text: raise DPI, not quality
If small text looks soft, the page has too few pixels. Raise the resolution. The Quality slider controls JPEG compression, not pixel count, so turning it up on a 72 DPI render still leaves the letters soft. If the text is sharp but surrounded by faint blocky smudges, that is compression, and raising the quality or switching to PNG fixes it.
JPG or PNG: which output format should you use?
Choose JPG when pages are mostly photos or when files must be small. Choose PNG when pages are mostly text, tables, charts or line drawings, where crisp edges matter more than size.
| JPG output | PNG output | |
|---|---|---|
| Compression | Lossy, defined in ITU-T T.81 | Lossless, defined by the W3C PNG specification |
| Quality control | Slider from 10 to 100, default 90 | None needed; nothing is discarded |
| Text and thin lines | Faint artifacts around sharp edges, more at lower quality | Edges exactly as rendered |
| Pages full of photos | Small files | Very large files |
| Background | White | White (pages are rendered on white, as on paper) |
| Accepted by upload forms | Almost everywhere | Most places; some forms ask for JPG only |
JPEG was designed for photographs. It splits the image into 8 by 8 pixel blocks and discards fine detail the eye is least likely to miss, which works well on smooth photo gradients and less well on black text on white, where the edges are exactly the fine detail. At a quality setting of 90 the effect is hard to see; at 40 it is obvious.
Both outputs have a white background. JPG cannot store transparency at all, and pdf.js paints each page white before drawing it, so PNG pages are white too. If you need a page element on a transparent background, a page render is the wrong starting point.
The same pixel math applies to both formats, and the same page limits. For a deeper comparison of lossless raster and vector graphics, the SVG vs PNG guide covers when a drawing should stay vector.
What if the PDF is a scan?
A scanned PDF is already a set of images, one per page, wrapped in a PDF. Rendering it to JPG draws those images again at the resolution you choose, and that has one consequence people often miss: a higher DPI than the scan's own resolution adds pixels, not detail.
Say an office scanner saved a letter at 200 DPI. Rendering it at 300 DPI gives a 2480 x 3508 pixel A4 image, but the extra pixels are filled in by scaling the 200 DPI original, so the text is no sharper than it was. Rendering at 150 DPI throws away a little of the scan's detail in exchange for a smaller file. For scanned documents, 150 DPI is usually the sensible choice unless you know the scan was made at 300 or more.
Two other things behave differently with scans:
- A scan has no text layer to lose, unless someone ran OCR on it. Text in the JPG is exactly as readable as it was in the PDF.
- A scanned PDF is often much larger per page than a typed one, because each page holds a full photo. It renders just as quickly, but it reaches the 200 MB file limit sooner.
If a scan came out sideways or upside down, fix the PDF first. The rotate PDF tool turns pages in the document itself, and every JPG rendered afterward comes out upright.
How do you convert only some pages?
Every page of the PDF is rendered, but you do not have to download them all. Press Show pages on the PDF's row to list each page with its own size, pixel dimensions and download icon, and save only the ones you need. Clicking a thumbnail opens that page large, so you can check it before saving.
For a long document where you need three pages out of eighty, it is faster to cut those pages out first. The extract PDF pages tool builds a smaller PDF from the pages you pick, and converting that renders three pages instead of eighty. The same approach handles PDFs over the 100-page limit: extract or split the part you need, then convert it.
Where do the page images work best?
The right settings depend on where the images are going. These combinations cover the common destinations:
| Destination | Resolution | Format | Why |
|---|---|---|---|
| Chat message or email body | 150 DPI | JPG, quality 80 to 90 | Readable on a phone, small enough to send quickly |
| Slide in a presentation | 150 DPI | PNG for text pages, JPG for photo pages | Taller than a 1080p screen, crisp on a projector |
| Upload form that wants an image | 150 DPI, or 72 for strict pixel caps | JPG | Accepted almost everywhere, small files |
| Printing a page as a picture | 300 DPI | JPG at 90 or PNG | Print-shop resolution for A4 and Letter |
| Web page preview or thumbnail | 72 DPI | JPG | Small file, loads fast |
| Cropping a detail from a drawing | 300 DPI | PNG | Most pixels, no compression smudging |
If a form caps the file size rather than the pixel size, lower the Quality slider before lowering the DPI. Text at 150 DPI and quality 70 is usually more readable than text at 72 DPI and quality 90, because resolution limits sharpness more than compression does.
What are the limits?
The converter refuses files and pages that would exhaust the browser tab's memory, and each refusal comes with a message that names the limit it hit.
| Limit | Value | What to do if you hit it |
|---|---|---|
| File size | 200 MB | Split the PDF or remove heavy pages first |
| Page count | 100 pages | Split the PDF into parts of 100 pages or fewer |
| Pixels per page | 40 megapixels at the chosen DPI | Choose a lower resolution |
| Longest side of a page | 16,384 pixels | Choose a lower resolution |
| Daily conversions | A daily limit per device | Try again the next day, or sign in for a higher limit |
The per-page limit matters mainly for large-format pages. An A4 page at 300 DPI is 8.7 megapixels, far below it. An A1 drawing sheet (594 by 841 mm) at 300 DPI would be 7016 x 9933 pixels, about 70 megapixels, and is refused; the same sheet at 150 DPI is about 17 megapixels and converts. The 16,384-pixel side limit catches tall pages: at 300 DPI, any page more than about 54.6 inches long passes it.
For PDFs over 100 pages, split the PDF into smaller files first. The split PDF guide covers splitting by page ranges, so you can convert only the section you need.
Why won't my PDF convert?
Each failure has its own message. These are the ones you are most likely to see, and what causes them.
"This PDF is protected with a password, so its pages cannot be read." The PDF has an open password, called the user password in ISO 32000's standard security handler. Without it, the page contents are encrypted and cannot be drawn. The converter does not try to guess or bypass passwords. Open the file in a PDF reader with the password, save a copy without protection, and convert that copy.
A PDF can also carry only an owner password, which restricts printing, copying or editing but does not stop anyone opening it. Such files open without a password in any reader, and pdf.js renders them the same way.
"This PDF could not be read." The file is damaged, incomplete or not a PDF at all. A download that stopped halfway is the usual cause. Download it again, or open it in a desktop reader and re-save it.
"This PDF has N pages." More than 100 pages. Split it first.
"Page N would be WxH pixels at D DPI." One page exceeds 40 megapixels or 16,384 pixels on a side at the chosen resolution. Pick a lower DPI.
"The PDF decoder did not finish downloading." pdf.js failed to load, usually because the connection dropped. Check the connection, remove the file and add it again.
If the images look different from your PDF reader, the most common reason is fonts. A PDF that does not embed its fonts relies on the viewer to supply them, and a missing font is drawn with a substitute, which changes letter shapes and spacing slightly. Rotated and landscape pages come out the way a reader displays them, because the page's own rotation is applied before rendering.
What changes, and what is lost, in the conversion?
The visible page survives. Almost everything else does not.
- Text layer: gone. The words are pixels. Keep the PDF if the text must stay searchable.
- Links and bookmarks: gone. An image has nowhere to store them.
- Vector sharpness: fixed at the chosen DPI. Zooming past that shows pixels.
- Page size in inches: replaced by a pixel size. The image carries no reliable print size of its own.
- Multiple pages: split into one file per page.
To print an image at the size of the original page, give the printing app the paper size and choose fit to page. A 2480 x 3508 pixel render of an A4 page, printed fit to page on A4 paper, comes out at the original size at 300 pixels per inch. Printed at "actual size", many apps fall back to a default density and the page comes out far too large or too small.
For a page that must look identical at any zoom, such as a logo sheet or a drawing, render at 300 DPI and output PNG. For a page that only needs to be read in a chat, 150 DPI JPG at quality 90 is plenty.
Is converting a PDF on Toolz private?
Yes. The PDF is opened and every page is rendered client-side inside the browser tab, and the file is never uploaded. pdf.js and its image decoders are served from Toolz.dev itself, not from a third party.
The daily limit check sends the tool name, a device identifier and your sign-in token if you have one; it does not include the PDF. After a batch, the page logs how many files converted, their total size and the output format. File names, page content and pixels are never sent. The images stay in the tab's memory until you remove the PDF, press Clear All or close the page. The tool is free, no signup.
Alternatives to an online PDF to JPG converter
On a Mac, Preview exports one page at a time: open the PDF, select a page thumbnail, choose File, then Export, pick JPEG and set the resolution. On Windows there is no built-in export, although the Snipping Tool can capture a page as it appears on screen, which gives only as many pixels as the page occupies on your display.
On the command line, Poppler's pdftoppm renders every page at a chosen resolution:
pdftoppm -jpeg -r 150 report.pdf report
That writes report-01.jpg, report-02.jpg and so on, with the same DPI arithmetic as above. It suits scripts and servers; the browser route suits one-off jobs with no installation.
Going the other way, from images back to one PDF, is the job of the JPG to PDF converter, which puts one photo on each page in an order you set. The image tools hub lists every converter in the set.
When you have a PDF ready, convert its pages to JPG at 150 DPI first, look at the result, and move to 300 only if the text needs it.
