PDF to JPG

Converting a PDF to images means one of two quite different things, and picking the wrong one accounts for most disappointing results. Rendering pages draws each page exactly as a viewer would display it — text, vector artwork, backgrounds and photographs all flattened together into a single picture at a resolution you choose. What you get is a faithful snapshot of the page.

Extracting images ignores the page entirely and reaches into the file for the photographs and graphics stored inside it, returning each one at its native size. Nothing is rendered and nothing is re-scaled, so what comes out is the original asset as the document's author embedded it.

The question that separates them is what you actually want. If you need the page — for a slide, a preview thumbnail, a printed proof — render it. If you need the photograph that happens to be on the page, extract it, because rendering would bake it into the surrounding layout at whatever size it was displayed.

DPI is how many pixels are generated for each inch of the original page, and it is the single setting that most affects both quality and file size. Around 72 DPI is enough for on-screen viewing and web thumbnails. Around 150 DPI is the general-purpose choice and looks clean on a modern high-density display. 300 DPI is print quality, and is what you want if the image will be placed in a printed document.

Going higher than you need is not free. Because pixels scale in two dimensions, doubling the DPI quadruples both the pixel count and roughly the file size, and beyond a point you are simply storing a more precise record of the same visual information. The reverse mistake is worse though — you cannot recover detail by enlarging a low-DPI export afterwards, so when in doubt render at the higher setting and scale down later.

Small text is the practical test. If the page has footnotes or fine print and they look ragged in the preview, the resolution is too low for the content, regardless of what the intended use is.

The three formats fail in different ways, and the content of your page decides which failure you can live with. JPG uses lossy compression tuned for photographs: it is excellent on continuous-tone imagery and produces the smallest files, but it introduces faint halos around hard edges — which is precisely what text and line art are made of. On a text-heavy page rendered at low quality, that shows as a grey fringe around every letter.

PNG is lossless, so text stays perfectly crisp and flat colours stay flat, and it supports transparency. The cost is size: a photographic page as PNG can be several times the JPG. WEBP sits between them, delivering close to PNG sharpness at close to JPG size, and every current browser supports it — though some older desktop software still does not.

As a rule of thumb: pages that are mostly text, diagrams or screenshots want PNG or WEBP; pages that are mostly photographs want JPG; and anything being handed to a system with unknown software support wants JPG or PNG, the two formats that everything has understood for decades.

Turning pages into images buys universality. An image opens on anything, embeds into a slide deck or a web page without a plugin, uploads to systems that reject PDFs, and looks identical everywhere because there is nothing left to interpret. For thumbnails, previews, social posts and quick visual sharing it is exactly right.

What it costs is everything that made the file a document. Text stops being text, so it cannot be searched, selected, translated or read aloud by a screen reader. Links stop working. Bookmarks and form fields are gone. File size usually goes up rather than down, because a compact page description has been replaced by millions of pixels.

So it is worth being clear about the goal. If you want to stop people editing the document, Protect PDF sets permissions without destroying the text layer. If you want it smaller, Compress PDF is the right tool. Converting to images to achieve either of those is a trade that costs more than it saves — but when you genuinely need pictures, it is the only thing that will do.