To combine images into one PDF, you typically need a tool that wraps multiple files into a single .pdf document container — one image per page, with the PDF format preserving print-ready sizing and text-searchable metadata. A combined PNG takes a fundamentally different approach: it stitches two to twelve images into one continuous raster canvas and exports the result as a single PNG file. Both approaches solve the underlying problem of keeping multiple images together in one shareable file, but they serve different downstream needs. A PDF is page-oriented and ideal for printable documents, multi-page packets, and formal submissions. A combined PNG is pixel-oriented and ideal for visual comparisons, before/after pairs, screenshot montages, design references, and quick sharing on platforms that don't accept PDFs. The Combine Images tool handles the PNG path: it decodes your local files, arranges them in a layout you choose, and exports a single PNG without uploading anything to a server.
What "Combine Images Into One PDF" Actually Means
The phrase "combine images into one PDF" carries two distinct meanings depending on what the reader is trying to accomplish. The first meaning is literal: produce a multi-page PDF document where each page contains one image, ready for printing, archiving, or attaching to an email. The second meaning is looser: produce a single file that contains multiple images bundled together, regardless of whether the file extension ends in .pdf or .png.
Most online guides for this query focus on the first meaning because PDF is a well-known document format. But the second meaning is more common in practice for everyday tasks like comparing two photos side by side, stitching a vertical screenshot set into one tall image, or building a grid of product photos for a marketplace listing. When the downstream use is sharing, posting, or embedding, a combined PNG is often a better fit than a PDF because nearly every chat app, social platform, and image viewer accepts PNG without conversion.
The Combine Images tool is built for the second interpretation. It produces a single PNG that contains your images arranged in a layout you choose, with the original pixel dimensions of each source preserved. It does not produce a PDF, and it does not wrap images in a document container.
When a Combined PNG Is the Right Answer
A combined PNG is the right output when you need a single raster image that visually contains multiple source images. Concrete scenarios where this fits better than a PDF include:
- Before/after comparisons: place two photos side by side at full resolution to show a transformation.
- Screenshot stitching: combine a tall vertical scroll capture or a sequence of screenshots into one continuous image.
- Product photo grids: arrange 4–12 product photos into a square or rectangular grid for a marketplace listing.
- Design mockup references: place multiple UI screenshots into one image for a presentation or design review.
- Social media montages: create a single image suitable for platforms that don't accept PDFs.
In each of these cases, the goal is a single image file, not a printable document. A PDF would force the reader to open a document viewer, scroll through pages, and possibly convert the file before sharing. A combined PNG opens directly in any image viewer, chat app, or browser tab.
How to Combine Images Into One PDF-Friendly File
The workflow below produces a single PNG that contains all your images in the order you specify. If you later need a PDF, you can use any image-to-PDF tool to wrap the combined PNG into a one-page PDF document.
- Open the Combine Images tool and select between two and twelve image files from your device. Supported formats are PNG, JPEG, WebP, GIF, AVIF, and BMP. The tool rejects SVG input because SVG can reference external resources or contain large render instructions that don't fit a bounded raster workflow.
- Select your files in the order you want them to appear in the output. The final arrangement preserves the order selected by the browser.
- Choose a layout: horizontal, vertical, or grid. Horizontal places images from left to right at their decoded pixel sizes. Vertical places them from top to bottom. Grid arranges them into a square-like matrix based on the image count.
- Set the gap between images (0 to 100 pixels) and pick a six-digit background color with the color picker. The background fills the canvas and the area between images.
- Click "Combine images," verify the output dimensions, and download the generated PNG.
All processing happens in the current browser tab. The tool decodes each file with createImageBitmap, draws the bitmaps onto a canvas without scaling, encodes the canvas as PNG using toBlob, and serves the result through a revocable object URL. Your source files never leave your device.
Choosing the Right Layout
The three layouts produce different output dimensions and different visual rhythms. Understanding how each one calculates its canvas helps you pick the right one before you start.
| Layout | Output Width | Output Height | Image Placement |
|---|---|---|---|
| Horizontal | Sum of all widths + total gap | Tallest image height | Left to right; shorter images centered vertically |
| Vertical | Widest image width | Sum of all heights + total gap | Top to bottom; narrower images centered horizontally |
| Grid | Sum of column widths + gaps | Sum of row heights + gaps | Centered in each cell; empty cells filled with background color |
For a horizontal layout with three images measuring 800×500, 1200×700, and 600×400 pixels, using a 20-pixel gap, the output canvas is 2640 pixels wide (800 + 1200 + 600 + 2 gaps of 20) and 700 pixels tall (the tallest image). The shorter 800×500 and 600×400 images are centered vertically within that 700-pixel height without being stretched.
Grid layout uses the ceiling of the square root of the image count to determine the column count. Four images produce a 2×2 grid, nine images produce a 3×3 grid, and ten images produce a 4×3 grid with two empty cells in the final row. Every cell uses the widest decoded image and the tallest decoded image as its bounds, so images keep their original aspect ratio and are centered inside their cell without stretching or cropping.
File Limits, Formats, and Transparency
The tool enforces several hard limits to keep memory usage bounded. Each source file must be no larger than 25 MiB, all selected files together must not exceed 100 MiB, and the combined canvas cannot exceed 8192 pixels on either side or 32 million pixels in area. Files whose extension looks familiar may still fail when their bytes are corrupt or their codec is unsupported by the browser's image decoder.
The output is always a single PNG. The tool uses the browser's required PNG encoder and does not target a specific byte size. PNG preserves sharp pixels and transparency in decoded inputs, but the selected opaque background color is painted first, so any transparent areas become that color in the exported file. If you need transparency preserved in the combined output, pick a background color that matches your downstream use or composite the result in dedicated software.
Animated GIF, WebP, and AVIF sources contribute only the frame decoded by the browser's image bitmap path. Animation, layers, EXIF metadata, color profiles, and original filenames are not preserved in the single PNG output. For print production or color-managed compositing, verify the exported PNG in dedicated software before sending it to a printer.
When You Need an Actual PDF Instead
If your downstream task genuinely requires a PDF document — for example, submitting a multi-page packet to a school, attaching a printable document to an email, or archiving images in a format that supports searchable text — a combined PNG is not the right output. In that case, use a dedicated image-to-PDF tool that wraps each image into its own page. The Image To PDF tool produces a multi-page PDF with one image per page, which is the standard format for printable document workflows.
For a broader guide on building PDFs from local images, see Turn Multiple Images into One PDF in Your Browser, which covers the PDF path from end to end. The canvas rendering that powers the Combine Images tool follows the standard CanvasRenderingContext2D drawImage behavior.
The short version: when you want a single image file containing multiple images, use Combine Images. When you want a printable, multi-page document, use an image-to-PDF tool. Both workflows run locally in your browser and keep your source files private.