PDF to Long Image Free — Convert PDF to One Scrollable PNG
A "long image" stitches every page of a PDF vertically into one tall PNG you can scroll through — the format social media users call a scroll screenshot. It lets you share a full document preview on Twitter/X, embed it in a Notion page, or send it on WhatsApp without requiring the recipient to have a PDF reader. This guide covers how it works, which DPI setting to choose, and what file sizes to expect.
- A long image is all PDF pages rendered and concatenated vertically into one tall PNG
- PDF.js renders each page to a canvas at your chosen DPI, then all canvases are stacked on a single tall canvas
- 72 DPI for social media, 150 DPI for balanced quality, 300 DPI for print-quality output
- A 10-page A4 PDF at 150 DPI produces roughly 3–5 MB — manageable for most sharing platforms
- The tool runs entirely in your browser via fusionpdf.pro/pdf-to-longimg — no file is ever uploaded
Most PDF sharing solutions require the recipient to open a PDF reader, navigate pages, and zoom in on their own. A long image removes that friction entirely — it is just an image file, viewable everywhere. The catch is that generating one cleanly, without broken page cuts or blurry text, requires rendering each page at the right resolution before stitching. That is what this guide explains.
What Is a Long Image or Scroll Screenshot?
A long image — also called a scroll screenshot or tall PNG — is a single image file that contains every page of a document arranged vertically from top to bottom. Instead of one image per page, you get one image per document. The result is a PNG file that can be several thousand pixels tall, which viewers scroll through the same way they would scroll a web page.
The format became popular on social media, where users wanted to share multi-page documents — resumes, reports, slide decks, contracts — as a single embeddable image rather than a PDF attachment. On Twitter/X and LinkedIn, images render inline in the feed; PDFs do not. A long image bridges that gap.
Paginated documents
PDFs with consistent page sizes — A4, Letter, slide decks — produce clean long images because every page stitches at the same width.
- Resumes and CVs
- Reports and whitepapers
- Slide decks exported to PDF
- Contracts and legal documents
Mixed-size documents
PDFs with pages of different sizes or orientations produce long images where page widths vary, leaving gaps or misaligned edges.
- Scanned books with varying margins
- Mixed portrait / landscape documents
- PDFs assembled from multiple sources
- Very long documents (canvas size limits apply)
The key difference between a long image and a normal per-page export is continuity: a long image lets the viewer's eye flow naturally from page to page without clicking a next-page button or switching tabs. For documents that tell a story — pitch decks, CVs, one-pagers — that continuity is a genuine advantage.
How to Convert a PDF to a Long Image (3 Steps)
FusionPDF's PDF to Long Image tool renders every page of your PDF onto individual canvases using PDF.js, then stacks them vertically into a single tall canvas and exports it as a PNG. The entire process runs in your browser — no file is sent to any server at any point.
Upload your PDF. Go to fusionpdf.pro/pdf-to-longimg. Click "Select PDF" or drag your file onto the page. The file is loaded into your browser's memory via the FileReader API — nothing leaves your device.
Choose your DPI and let pages render. Select your desired resolution: 72 DPI for screen use, 150 DPI for a balanced output, or 300 DPI for print quality. PDF.js renders each page to an individual canvas at the chosen DPI. All canvases are then stacked vertically onto one tall master canvas.
Download your single PNG. Click "Download PNG". The browser exports the combined tall canvas as a single PNG file. All pages are seamlessly stitched and ready to share — no page gaps, no borders between pages unless they were part of the original PDF design.
Tip for large documents: If your PDF has more than 20 pages, consider using 72 DPI or splitting it into sections first with the Split PDF tool. Very long documents at 300 DPI can approach browser canvas dimension limits on some devices.
How It Works Under the Hood: PDF.js and Canvas Stitching
The conversion process uses two browser APIs: PDF.js for PDF rendering and the HTML Canvas API for image assembly. PDF.js is Mozilla's open-source PDF rendering engine that runs entirely in JavaScript — the same engine powering Firefox's built-in PDF viewer. It reads the PDF's content stream and renders each page as a bitmap on an HTML canvas element at the resolution you specify.
Here is the sequence of operations the tool runs:
- The PDF file is loaded into memory as an ArrayBuffer via the FileReader API.
- PDF.js parses the PDF structure and reports the total page count.
- For each page, PDF.js renders the page to an individual
<canvas>element at the target DPI (the page's point dimensions multiplied by the DPI scaling factor). - The tool calculates the total height of the combined image (sum of all individual page heights) and the maximum width (widest page).
- A single master canvas is created with those dimensions.
- Each page canvas is drawn onto the master canvas in sequence, top to bottom, using
drawImage(). - The master canvas is exported to a PNG data URL via
canvas.toBlob('image/png'), which the browser delivers as a file download.
DPI Settings and Their Effect on File Size
DPI (dots per inch) controls the pixel density at which each PDF page is rendered. A higher DPI means more pixels per page, which produces a sharper image — but a proportionally larger file. For a long image, file size matters because you're combining all pages into one: a 10-page A4 PDF at 300 DPI produces an image over 8,000 pixels tall, which most sharing platforms will compress or reject.
| DPI | Typical output (10-page A4) | Best for |
|---|---|---|
| 72 DPI | ~0.8–1.5 MB PNG, ~840 × 11,900 px | Twitter/X, LinkedIn, WhatsApp (as document) |
| 150 DPI | ~3–5 MB PNG, ~1,750 × 24,750 px | Notion embeds, portfolio pages, email |
| 300 DPI | ~10–20 MB PNG, ~3,500 × 49,500 px | Print, high-resolution archiving |
PDF dimensions are measured in points (1 point = 1/72 inch). An A4 page is 595 × 842 points. At 72 DPI the rendered canvas is 595 × 842 pixels — one pixel per point. At 150 DPI it becomes 1,240 × 1,754 pixels. At 300 DPI it reaches 2,480 × 3,508 pixels. For a 10-page document, multiply the page height by 10 to get the total image height for the long image.
Browser canvas limits: Most Chromium-based browsers cap canvas dimensions at 16,384 × 16,384 pixels. A 10-page A4 document at 300 DPI produces a canvas ~49,500 pixels tall — well above this limit. If you hit this ceiling, the browser will silently produce a blank or partially rendered output. Switch to 150 DPI or split the PDF first.
Use Cases: Social Media, Notion, Portfolio, WhatsApp
The long image format is most useful when the recipient is a platform or person that cannot or will not open a PDF. It converts a multi-page document into the universal format — an image — while preserving the full reading experience by making it scrollable.
Twitter/X and LinkedIn
Both platforms render images inline in the feed and allow up to 4 images per post, each up to 5 MB. Sharing a PDF as a long image means your document appears immediately without requiring followers to click a link, download a file, or open a separate viewer. Carousels of separate page images work too, but a single long image is faster to produce and keeps the full document in one shareable unit. Use 72 DPI to stay comfortably under the 5 MB per-image limit on most posts.
Notion and Confluence
Notion supports inline image embeds via drag-and-drop or the /image block. A long image embedded this way gives readers a scrollable preview directly inside the page without leaving Notion. This is particularly useful for team wikis embedding external reports, PDFs of specifications, or design documents. At 150 DPI, the text stays legible when Notion viewers zoom in on the embedded image.
Portfolio screenshots and document previews
Designers, writers, and researchers often want to show a PDF document as part of a portfolio without making visitors download anything. A long image works as a visual preview — embed it on a portfolio page, link it from a bio, or use it as a project thumbnail. The PNG format ensures it stays sharp at any size and is losslessly compressed for archiving.
WhatsApp sharing
WhatsApp compresses photos sent as images but delivers files sent as documents at full resolution. A long image generated at 72 DPI and sent as a "Document" (not a "Photo") arrives without compression and is immediately viewable by the recipient by scrolling down — no PDF reader required, no app switch needed.
Long Image vs PDF Viewer Embed vs Screenshot Tool
There are three common ways to share a PDF visually without requiring the recipient to download it: convert it to a long image, embed a PDF viewer, or take screenshots of each page. Each approach has different trade-offs in portability, quality, and effort. Here is an honest comparison.
| Method | Works on all platforms | Text selectable | Effort | File size |
|---|---|---|---|---|
| Long image (FusionPDF) | Yes | No (image) | Low — 3 steps, browser-based | 3–5 MB (150 DPI, 10 pages) |
| PDF viewer embed (iframe) | Varies — requires a server | Yes | High — requires hosting and HTML | Same as source PDF |
| Per-page screenshots | Yes | No (image) | High — one screenshot per page | Multiple files, harder to share |
| Adobe Export to Image | Yes | No (image) | Medium — requires Acrobat Pro | One file per page, not stitched |
The long image approach wins on portability and effort. Its main disadvantage is that text in the image is not selectable or searchable — it is rendered pixels, not characters. If searchability matters, a PDF viewer embed is worth the extra complexity. If you just need to share a document preview quickly and universally, the long image is the right tool.
When to use PDF → individual images instead: If you need separate files per page — for a presentation slide library, for uploading to a platform that only accepts one image per post, or for feeding into an image processing pipeline — use the PDF to Image tool, which exports each page as a separate PNG or JPG.
What DPI should I use for social media?
72 DPI is enough for Twitter/X and LinkedIn previews — screens display at 72–96 DPI and a higher resolution does not improve visual quality on social feeds. Use 150 DPI if you want the image to look sharp when a viewer zooms in on mobile. Reserve 300 DPI for print-quality outputs or situations where the PNG will be used in a presentation or document. For most social media use, 72 DPI keeps the file well under the 5 MB per-image limit most platforms enforce.
Can I convert only specific pages of my PDF?
FusionPDF's PDF to Long Image tool currently processes all pages in the document. If you only need a subset of pages, use the Split PDF tool first to extract the pages you want, then run the long-image conversion on the resulting smaller PDF. Split takes under a minute and the result feeds directly into the long-image tool.
What is the maximum PNG canvas size browsers support?
Most modern browsers cap canvas dimensions at 16,384 × 16,384 pixels (Chrome, Edge) or 32,767 × 32,767 pixels (Firefox, Safari). A 10-page A4 PDF at 150 DPI produces a canvas roughly 1,240 × 17,500 pixels — within Chrome's limit. At 300 DPI the same document exceeds 49,000 pixels tall, which will silently fail or produce a blank output in Chromium. If your export looks blank, switch to 150 DPI or split the PDF into smaller sections first.
Can I get a JPG instead of PNG?
The tool exports PNG by default because PNG is lossless and preserves text sharpness at all zoom levels. JPG introduces compression artifacts that can make fine text look blurry, particularly at low quality settings. If you need a smaller file and can accept some quality loss, convert the downloaded PNG to JPG using any image editor after export. For most use cases — social media, Notion, email — the PNG at 72 DPI is already compact enough without needing JPG conversion.
How do I share a long image on WhatsApp?
WhatsApp compresses photos automatically when sent as an image, which degrades a long PNG significantly. The correct approach is to generate your long image at 72 DPI to keep the file under 5 MB, then share it as a "Document" rather than a "Photo" — tap the attachment icon, choose "Document", and select the PNG file. Sharing as a document bypasses WhatsApp's image compression entirely and delivers the full-resolution PNG to the recipient, who can then scroll through it in their file viewer.
Convert Your PDF to a Long Image — Free, No Upload
All pages rendered and stitched vertically in your browser. Choose 72, 150, or 300 DPI. Download a single scrollable PNG in seconds — no file ever leaves your device.