How converting a PDF to images actually works
A PDF is a layout container, not a picture. Each page describes text, vector shapes, and embedded images in a way that a PDF reader interprets and draws on demand. To turn a page into an image you have to render it — run that description through a rasteriser that paints every glyph and shape onto a pixel grid. That is exactly what this tool does, using a WebAssembly build of PDF.js, the same open-source engine that renders PDFs inside Firefox and Chrome.
Because rendering happens on a pixel grid, two choices control the result: the resolution (DPI) and the output format. DPI decides how many pixels each inch of the page becomes, so it governs sharpness and file size. The format decides how those pixels are stored — losslessly for crisp text, or with compression for smaller photo-heavy pages. Get those two right and the image is indistinguishable from opening the PDF itself.
For everyday documents the whole process runs in your browser. Your PDF is read into memory, handed to the PDF.js worker on a background thread so the page stays responsive, and each page is drawn onto an off-screen canvas that is then encoded to PNG, JPG, or WebP. Nothing is uploaded; the file never leaves your device. Only when a document is large — more than 10MB or more than five pages — do we hand it to a server worker that can render it without straining the browser.
Choosing the right DPI for the job
DPI — dots per inch — is the single most important setting. A PDF page is defined in points at 72 per inch, so a DPI of 72 reproduces the page at 1:1 pixel scale. Doubling to 144 doubles the width and height; 300 DPI produces roughly four times the linear resolution of screen rendering. More pixels mean sharper text and the ability to zoom or print without jaggies, at the cost of a larger file.
For images that will only ever be viewed on a screen — a thumbnail, a preview, a social post — 96 DPI is plenty and keeps files small. Step up to 150 DPI when you want text to look crisp in a slide deck or a document preview. Reach for 300 DPI whenever the image will be printed: it is the long-standing print standard and the point at which individual pixels become invisible to the eye at normal viewing distance. 600 DPI is reserved for archival scans and fine-detail reproduction; it produces very large files, so only use it when the extra detail genuinely matters.
A practical tip: render at the DPI you actually need rather than the maximum. A five-page contract at 600 DPI can be tens of megabytes per page, while the same contract at 150 DPI is a fraction of the size and still perfectly legible on screen. You can always re-run the conversion at a higher DPI if you discover you need it.
PNG, JPG, or WebP — picking the output format
PNG is lossless. Every pixel of the rendered page is preserved exactly, edges stay razor-sharp, and transparency is supported. That makes it the default choice for pages dominated by text, tables, diagrams, and line art — anything where soft, blurry edges would look wrong. The trade-off is size: a text page at high DPI is larger as a PNG than as a JPG.
JPG uses lossy compression tuned for photographs. On a page that is mostly a scanned photo or a full-bleed image, JPG produces a much smaller file with no visible difference. On crisp text, however, JPG introduces faint ringing artifacts around the letters, so it is the wrong choice for documents that are mostly type. JPG also has no transparency, so any transparent areas are flattened onto white.
WebP is the modern compromise. It compresses sharp content nearly as well as PNG and photographic content nearly as well as JPG, supports transparency, and is now supported in every current browser. For most PDF-to-image conversions WebP gives the smallest file at a given quality, which is why it is worth choosing when broad compatibility with very old software is not a concern.
Per-page selection, combining, and batch download
You rarely need every page. After you drop a PDF, the tool shows a thumbnail of each of the leading pages with a checkbox so you can extract just the ones that matter — a single signature page, one chart, or the cover. 'Select all' is one click away when you do want the lot. Only the pages you tick are rendered, which keeps conversions fast.
When you convert more than one page you get a ZIP containing every page as a separate image, each named by its page number so the order is obvious. If you would rather have a single file, switch on 'Combine into one tall image' and the selected pages are stacked vertically into one continuous PNG, JPG, or WebP — ideal for sharing a whole document as a single scrollable picture.
On the free plan you can extract up to five pages per PDF, which covers the overwhelming majority of real tasks. Long documents are heavier to render, so unlimited page extraction is a Pro feature — but you can always work through a long PDF five pages at a time for free.
Privacy, common uses, and the reverse trip
Because small PDFs are rendered entirely in your browser, this tool is safe for sensitive material — contracts, bank statements, medical forms, internal reports. The bytes stay on your machine; there is no upload, no cloud copy, and nothing for anyone to leak. That client-side model is the whole reason to prefer an in-browser renderer over a website that requires you to hand over the file.
People reach for PDF-to-image conversion constantly: pulling a single page out of a report to drop into a slide, turning an invoice into an image for an expense tool that won't accept PDFs, grabbing a diagram to annotate, or making a shareable preview of a document for chat. Rendering to an image guarantees the recipient sees the exact layout you do, with no font substitution or reflow.
When you need to go the other way, our image-to-PDF tool assembles one or many images back into a single PDF with control over page size and order, and our OCR tool can pull selectable text out of a rendered page. Together they cover the full round trip between documents and images — all in the browser, all without surrendering your files.