PDF to JPG conversion turns every page of a PDF into a separate JPEG image at the rendering scale and JPEG quality you choose, and the PDF to JPG Converter from Lizely does this locally in your browser for any non-empty PDF up to 25 MiB. The PDF.js rendering engine loads only after you press the button, parses the document, and flattens each page onto a white background before encoding it as image/jpeg with a zero-padded page number in the filename. Because the work happens on your device, your original document and the generated images never leave your machine and are never uploaded to a conversion server. Every finished page appears with its exact pixel dimensions and gets its own download button, and changing the file, scale, or quality invalidates the old result so the controls never describe stale images. This approach renders the complete visible page — text, vector paths, photos, annotations, and transparency all combined into one image — rather than extracting only the embedded picture objects inside the PDF.
PDF to JPG or PDF to PNG: Which Format Fits the Task
Both formats are image containers, but they behave very differently once your PDF pages are converted. JPG is a lossy format that compresses photographic content into small files at the cost of some fine detail. PNG is a lossless format that preserves every pixel exactly, supports a transparency channel, and is the better choice for diagrams, screenshots, and archival copies. The keyword "convert PDF to JPG or PNG" usually hides a real decision: which output format matches the destination?
Use JPG when the receiving system expects a common photographic image, when page transparency is unnecessary, and when smaller lossy files are acceptable. Use PNG when you need lossless output, crisp diagrams with sharp edges, or transparent regions. Lizely offers a dedicated PDF to PNG tool for the lossless case, with the same local-rendering approach but a different encoder and the ability to preserve alpha.
| Property | JPG (PDF to JPG Converter) | PNG (PDF to PNG) |
|---|---|---|
| Compression type | Lossy (0.60–1.00 quality) | Lossless |
| Transparency channel | No — pages flattened to white | Yes — alpha channel preserved |
| Typical file size | Smaller for photographic pages | Larger, but deterministic |
| Best for | Photos, web sharing, email attachments | Diagrams, screenshots, archival copies |
| Re-encoding quality | Degrades with each save | Stable across re-saves |
| Processing location | Browser, no upload | Browser, no upload |
How to Convert a PDF to JPG in Your Browser
The conversion workflow is short and explicit. Each step corresponds to a control on the tool page, and the browser enforces the safety limits at the moment you press the button.
- Choose one non-empty PDF up to 25 MiB. Use the file picker to select a single PDF from your device. Review the page-count and pixel safety limits displayed on the page before you continue, because the browser enforces them in advance and will refuse oversized or empty files.
- Select a rendering scale and JPEG quality, then click Convert to JPG. Scale controls how many output pixels each page produces; JPEG quality controls the encoder's detail retention between 0.60 (smaller files, more compression artifacts) and 1.00 (larger files, finer detail). Press the button to start the job.
- Preview the generated pages and download each zero-padded JPG file separately. Each page appears with its exact pixel dimensions and an individual download button. Filenames include a zero-padded page number so downloads sort in document order. Changing the file, scale, or quality invalidates the old result so controls never describe images generated with earlier settings.
What "Rendering a Page" Actually Means
A PDF page can contain many kinds of content: selectable text, vector paths, embedded photographs, annotations, transparency, and several coordinate systems. Rendering combines all of this visible content into one image that matches the browser's PDF interpretation, using the PDF.js library. The PDF to JPG Converter loads PDF.js and its worker on demand rather than as part of the page's initial bundle, and the shared worker URL can be cached and reused by the other PDF image tools on the site.
Rendering is not the same as extracting embedded images. Extracting pulls out the original picture objects that the PDF happens to reference, which is useful for recovering a specific graphic but skips text, vector drawings, and annotations. Rendering, by contrast, captures everything that is actually visible on the page. For image-recovery tasks, Lizely offers a separate Extract Images from PDF tool that exports JPG and simple RGB or grayscale image objects without rasterizing the page.
Because rendering produces a flattened image, the output does not preserve editable text, vector objects, layers, links, forms, or accessibility structure. If those document features are your real target, use a text extractor, a link extractor, or a form tool rather than a raster converter. The original PDF is never changed by the converter, and every downloaded image is a newly rendered derivative.
Scale, Quality, and the Output You Get
Scale is a multiplier applied to each page's base pixel dimensions during rendering. At scale 1, a page is rendered close to its original PDF point size. At scale 2, every dimension doubles, producing roughly four times the pixel count and a much larger file. A standard US Letter page measures 612 by 792 PDF points; at scale 1 the output is 612 by 792 pixels, and at scale 2 the output is 1224 by 1584 pixels, which is 1224 × 1584 = 1,938,816 pixels or about 1.94 megapixels for that one page. A higher scale can make small text easier to read in the output image, but it also increases memory use, processing time, and download size.
JPEG quality controls lossy image encoding from 0.60 to 1.00. Higher quality usually retains more visible detail but never restores detail that was absent from the source PDF. A page that is blurry or low-resolution in the original document will not become sharp at scale 4 with quality 1.00, because the converter cannot invent pixels the source does not contain. The tool never promises a particular file size, DPI, or print quality, because those outcomes depend on the page dimensions and the content of each page.
Every page is flattened onto a white background before JPEG encoding. This is intentional: JPEG has no transparency channel, so any transparent region in the source PDF would otherwise become an unpredictable dark or off-color area in the output. Flattening guarantees consistent backgrounds and predictable colors regardless of the source page's transparency settings. The output MIME type is explicitly image/jpeg.
Browser Safety Limits and When a PDF Cannot Convert
The browser enforces processing limits before and during conversion. These are practical constraints on rendering work, not statements about whether a PDF is safe or trustworthy to open. The current limits are:
- One file per conversion, up to 25 MiB in size
- No more than 40 pages in the selected PDF
- No rendered page above 12,000 pixels on either side
- No rendered page above 40 megapixels
- No conversion whose planned total pages exceed 100 megapixels
If a planned page would exceed 12,000 pixels on a side, 40 megapixels, or push the total above 100 megapixels, the preflight check blocks the conversion. The fix is to lower the rendering scale or split the source document with the Split PDF tool first and convert the parts separately.
A damaged, encrypted, unsupported, or unusually complex PDF can still fail even when it passes preflight, and password protection is not bypassed. Conversion begins only after you press the button, and starting a new conversion cancels the previous job. Temporary object URLs and canvases are released when results are replaced or the component closes, so abandoned work does not accumulate in memory.
Picking the Right Lizely Tool for the Job
JPG is the right output when the destination expects a common photographic format, transparency is unnecessary, and smaller lossy files are acceptable. PNG is the right output when lossless detail, transparent backgrounds, or crisp vector edges matter, and the dedicated PDF to PNG tool handles that case with the same local-rendering pipeline. For a single vertical graphic that stacks every page into one tall image, the PDF to Long Image tool produces one tall PNG with adjustable scale and spacing between pages.
For embedded images only, the Extract Images from PDF tool exports the picture objects without rasterizing the page. For merging the resulting JPGs back into a single PDF, the JPG to PDF tool combines them locally with selectable page sizes and orientation handling. The original PDF is never modified by the PDF to JPG Converter, and the same engine and the same safety limits apply whether you convert a one-page receipt or a forty-page report, so your document and its images stay on your device throughout the entire workflow.