Combining PDF pages into a single image means stacking every page of a PDF into one tall PNG that you can scroll through from top to bottom, instead of handling multiple image files or losing pages across separate downloads. The output is a single lossless image file — not a PDF, not a set of separate per-page images, not editable text — and the converter constructs it by rendering each PDF page onto its own canvas with the PDF.js library, then drawing those canvases one beneath the next onto a combined canvas whose width is set by the widest rendered page. Every step runs in your browser, so the source PDF is never uploaded to a server. You pick a rendering scale and a pixel gap between pages before the conversion starts, the tool preflights every page's scaled dimensions and the complete final-canvas layout, and only after that preflight succeeds does it encode the long PNG. The result keeps the visual content of every page — text, vector artwork, photographs, fonts, clipping paths — as it was originally painted on the document.
What "Combine PDF Pages Into One Image" Actually Delivers
The end product is one PNG file containing every page of the PDF arranged vertically, top to bottom, in the same order they appear in the source document. It is a flat raster image, which means it shows what was painted on each page but does not carry the document's interactive structure. Selectable text, live links, form controls, editable annotation objects, layers, document metadata, and the original internal PDF image objects are not preserved in the output. The image is encoded as lossless image/png, so each pixel you see corresponds exactly to a pixel rendered from the source page; there is no JPEG-style compression artifact introduced by the converter.
Because the renderer treats every page as a picture, mixed page sizes and mixed orientations are not a problem. The combined canvas uses the widest rendered page as its width, and each narrower page is placed horizontally in the center so it does not stretch to fill the wider canvas. You can specify a gap from 0 to 32 pixels between neighboring pages, and that gap area plus any unused side margins are kept white so page boundaries remain visually clear in the final stack.
When a Single Stacked Image Beats a Multi-Page PDF
Combining pages into one image is the right call when the receiving end of your document only works with images, not PDFs. Many chat and messaging apps display PDF attachments awkwardly, show only a generic icon, or refuse inline previews altogether, while a single PNG behaves like any other picture. Social platforms and forum posts that limit you to one image per submission also benefit from a stacked image — you keep every page of a short reference or a presentation in one upload instead of cutting it into several files.
The single-image format also suits a few non-sharing tasks. Reviewing a slide deck in one long scroll on a phone is often easier than flicking between PDF pages, and embedding a multi-page reference into a document, wiki page, or static site that only accepts pictures works without an iframe. Archiving a small printed handout as one image keeps the pages physically attached in a single file, which makes it harder for individual pages to be lost or detached over time. None of these situations need the structural PDF — they just need the visual content in a single, easily-shared file.
Combine PDF Pages Into One Image With the Long PNG Tool
The browser-based PDF to Long Image tool builds that single stacked PNG locally on your device. Before any rendering begins you can tune the scale and the gap between pages, and a preflight pass goes over every page so the tool only encodes the long image when the final canvas will fit inside the safety limits.
- Open the tool and pick the PDF. Click the file selector and choose one PDF from your device. The source file can be up to 25 MiB and up to 40 pages; encrypted, damaged, unsupported, or over-limit documents surface a clear error before any rendering starts.
- Set the rendering scale and the gap between pages. Use the scale control to choose how large each page is rasterized before it is added to the stack, and pick a pixel gap (0 to 32 pixels) for the visible white space between pages. Higher scale sharpens small text and thin lines at full zoom but increases width, height, and download size quickly.
- Click Convert to Long PNG. The converter first calculates every page's scaled viewport and the complete combined canvas. Final encoding only starts once this preflight completes, so you will not see a partial or oversized result if a late page would push the canvas past a ceiling.
- Review the combined dimensions and page count. After preflight, the tool reports the long image's total width, total height, and the number of pages in the stack so you can confirm the result before downloading.
- Download the single PNG. Click the download control to save the long image. The filename is derived from your PDF name with the .pdf suffix stripped case-insensitively, desktop-unsafe characters replaced, and a -long.png suffix appended.
Picking a scale and a gap that fit your plan
If the goal is sharing in a chat or a quick upload, a lower scale keeps the PNG small enough to send and fast to view on the receiver's connection. If the image needs to stay readable when someone zooms or opens it on a large screen, raise the scale enough that the smallest text you care about stays legible without visible pixelation. The gap is mostly cosmetic — pick a small gap for a tight scroll that reads as one continuous strip, or a wider gap if you want each page to behave like its own panel inside the same image.
How Mixed Page Sizes Are Placed Inside the Stack
Real documents rarely have identical page dimensions, and the long-image converter is built for that. As soon as rendering finishes for each page, its scaled dimensions feed into the layout calculation. The widest page sets the total canvas width; every other page, regardless of orientation or page size, is dropped in centered along the horizontal axis at that width. Nothing stretches to fill — a narrow portrait page sits between matching white side margins rather than being pulled sideways to match a landscape page, and a landscape page never compresses down to fit inside a narrower canvas.
Gap selection is independent: each page simply lands beneath the previous one at the pixel distance you chose. Because pages can be different heights, the long PNG's total height is the sum of every page's scaled height plus the gaps between them, not a multiple of a fixed page size. The renderer draws each per-page canvas onto the combined canvas using coordinates computed from that running total, and the final PNG keeps every page in its original top-to-bottom order.
Limits That Decide Whether the Stack Fits in One PNG
Every step of the conversion is bounded, and a long image can hit a limit on height or total size even when its individual pages are modest. The converter reports the combined width, combined height, and page count after preflight so you can spot a near-miss before encoding, but the underlying ceilings are fixed and worth knowing.
| Limit | Maximum value |
|---|---|
| Source PDF file size | 25 MiB |
| Page count in the PDF | 40 pages |
| One rendered page | 12,000 pixels on either side, or 40 megapixels |
| All page renders combined | 100 megapixels |
| Final long-image canvas | 12,000 pixels per side, and 100 megapixels |
The two ceiling values that matter most in practice are the 12,000-pixel side limit on the final image and the 100-megapixel aggregate. A long document can reach the height cap even when every individual page renders small — add up thirty portrait pages at moderate scale and the total height easily crosses 12,000 pixels. When that happens, drop the rendering scale, split the work, or export every page as a separate PNG instead of stacking them into one tall image.
When a Single Long Image Isn't the Right Format
A long stacked PNG is purpose-built for one picture per document, and it has trade-offs that matter in other settings. Very tall images can be awkward inside printers, email clients that size-fit images to the message body, basic image editors with limited canvas heights, and social platforms that crop or scale unusual aspect ratios. If any of those is your destination, separate per-page images or a different output format may work better.
| Output option | Use when | Processing location |
|---|---|---|
| PDF to Long Image — one stacked PNG | One picture must show every page of a short PDF, end to end, as a scrollable strip you can share as a single file. | Renders and stacks in the browser, never uploads the PDF. |
| PDF to PNG — one PNG per page | Each page needs to be its own file at full lossless quality, ready to drop into image editors or post one at a time. | Renders one page per PNG, never uploads the PDF. |
| PDF to JPG — one JPG per page | Smaller, lossy per-page images are fine and file size matters more than bit-exact pixel quality. | Renders one page per JPG as smaller lossy images, never uploads the PDF. |
The original PDF stays untouched in every case — none of these converters rewrite, restructure, or upload the source document. If the document is purely structural and needs to keep selectable text, live links, fillable form fields, or editable annotations, rasterizing into one PNG is the wrong direction; stay with a PDF-native workflow instead. If the goal really is one tall picture of every page, the long-image path is the focused option.