Image Splicer

Image splicing (also called image merging, photo collage, or image stitching) combines multiple separate images into a single composite image file. Our tool supports 13 different layout modes including horizontal, vertical, grid, asymmetric (left-big/right-big), diagonal, pyramid, and magazine-style collage arrangements. Unlike basic joiners, our splicer preserves each image's original aspect ratio so nothing ever looks stretched or distorted.

Absolutely not. This tool runs 100% in your browser using JavaScript and the HTML5 Canvas API. Here's what happens technically when you upload images: the browser's FileReader API reads your files into memory (RAM) as base64 data strings. All processing — layout calculation, resizing, compositing, encoding — happens entirely within your device's browser process. Your images are never transmitted over the network, never stored on any server, and are released from memory as soon as you close the tab. This architecture provides bank-level privacy for sensitive documents like ID cards, medical records, or personal photos.

You can upload images in JPEG (.jpg, .jpeg), PNG (.png), WebP (.webp), and GIF (.gif) formats. For output/download, you can choose between PNG (lossless, supports transparency — ideal for print and graphics), JPEG (lossy compression with adjustable quality 10-100% — ideal for photos and web sharing where small file size matters), and WebP (modern format offering ~25-35% smaller files than JPEG at equivalent quality — ideal for modern web usage). There are no format conversion fees or limitations.

There's no artificial limit on the number of images. Since all processing happens locally in your browser, the practical limit depends on your device's available RAM (memory). Based on our testing: most smartphones handle 8-15 images comfortably, typical laptops handle 20-50 images, and workstations with 16GB+ RAM can process 100+ images. If you encounter performance issues with very large numbers of images, try using fewer images or the Original Size mode which requires less computation per image.

Yes! Simply drag and drop images in the image list to reorder them. The order directly determines how images are arranged in the final splice — first image = first position. Our drag-and-drop system includes visual feedback: the dragged item shows a semi-transparent preview with slight rotation, and the target position highlights with a dashed border. This makes reordering intuitive even with many images. On touch devices, you can also use the position numbers to understand the current sequence.

The three sizing modes control how images are fitted into their layout cells:

• Auto Fit (recommended): Each image is scaled down proportionally to fit within its cell while maintaining its original aspect ratio. Uses the fitContain algorithm (similar to CSS object-fit: contain). This prevents any stretching or squashing. Smaller images may have whitespace around them; larger images are scaled down.
• Equal Size: All images are normalized to the same dimensions (based on the smallest image's proportions). Good when you want uniform-looking cells regardless of source image sizes.
• Original Size: Images keep their native pixel dimensions. The canvas expands to accommodate the largest image. May result in uneven layout if images have very different sizes. Best when all source images already have similar dimensions.

Yes! Check the "Transparent background" checkbox and select PNG as the output format (JPEG and WebP do not support transparency). This produces a PNG file with an alpha channel where empty areas are transparent. Common use cases include: creating overlays to place on other backgrounds, generating assets for graphic design software, making stickers or watermarks, and producing images for websites with non-solid backgrounds. Note that transparent backgrounds only work well with the Auto Fit or Equal sizing modes — Original Size mode may leave irregular transparent gaps.

The maximum output size is determined by your browser's Canvas implementation. Most modern browsers support canvas dimensions up to 16,384 × 16,384 pixels (268 megapixels). However, actual achievable size depends on available memory. Practical guidelines: Chrome/Edge typically handle up to 8192×8192 reliably, Safari supports up to 16384×16384, Firefox supports up to 12328×12328. For very large collages (e.g., combining 20+ high-resolution photos), we recommend using fewer images, downsizing source images first, or choosing a layout that minimizes total canvas area. If you hit the limit, the browser will show an error rather than producing corrupted output.

Yes! Use the "Border Width" setting (0-20 pixels) to add a uniform border around every image in the collage. Customize the "Border Color" to match your design needs — white borders create a classic framed look, black borders provide strong separation, and colored borders can match brand colors or themes. Borders are rendered as solid-color rectangles behind each image (underlay), so they don't overlap or obscure any image content. Combined with the Spacing setting, you can create various styles: zero spacing + visible borders = grid with frames; larger spacing + thin borders = minimal gallery look; thick borders + zero spacing = tiled mosaic effect.

100% free, forever, no catches. There are no premium tiers, no trial periods, no credit card requirements, no hidden fees, and no watermarks on downloaded images. We don't even require you to create an account or provide an email address. All 13 layout modes, all output formats, unlimited usage — everything is free. Our tool is supported as part of the FreeToolCenter suite of privacy-first utilities. We believe essential productivity tools should be accessible to everyone without paywalls.

Photoshop is a professional-grade image editor with extensive features, but for simple image merging tasks, our splicer offers significant advantages:

Yes, fully supported! Our image splicer uses responsive design that adapts to any screen size. Mobile-specific features include:

• Touch-friendly uploads: Tap to access your phone's photo gallery and select multiple images at once
• Swipe-to-reorder: Touch and drag image thumbnails to rearrange sequence (works alongside desktop drag-and-drop)
• Large tap targets: Rotation and delete buttons are sized for easy finger tapping (44px minimum touch target)
• Responsive layout grid: The 13 layout options automatically reflow into a scrollable grid on narrow screens
• Tested browsers: iOS Safari 14+, iOS Chrome, Android Chrome, Android Firefox, Samsung Internet

Tip: For best mobile experience, hold your device in landscape orientation when reviewing the preview — this gives more screen real estate to the wide-format collages.

Partially yes — with caveats. Once the page has fully loaded (all HTML, CSS, and JavaScript downloaded), the core splicing functionality works completely offline:

• Upload images from local storage (via File API, cached after initial load)
• Drag-drop reordering works offline
• Individual image rotation works offline
• All 13 layout modes work offline
• Preview generation works offline
• Download result works offline

What requires internet: Initial page load (downloading HTML/CSS/JS bundle, approximately 150KB). After that first load, the service worker could cache everything for true offline operation — this PWA feature is on our roadmap.

We support all modern browsers with HTML5 Canvas 2D Context support:

Key requirement: The browser must support the canvas.toBlob() method with JPEG and WebP encoding. WebP output requires Chrome 90+, Firefox 93+, Edge 90+, or Safari 16+. If your browser doesn't support WebP, simply choose PNG or JPEG output instead — all other features remain identical.

Yes! Individual image rotation is one of our unique features. Each image thumbnail shows two rotation buttons when you hover/tap: ↺ (rotate left 90° counter-clockwise) and ↻ (rotate right 90° clockwise). Here's what happens technically when you rotate:

1. A temporary hidden Canvas element is created
2. The source image is drawn onto this canvas with the appropriate rotation transform (using ctx.rotate())
3. The rotated canvas is exported back as a new image (the dimensions swap: a landscape photo becomes portrait after 90° rotation)
4. This new rotated image replaces the original in the image list, and the display updates instantly
5. You can rotate multiple times (90° → 180° → 270° → 360°=0°) cycling through all four orientations

Common use cases for rotation: Fixing sideways photos taken with phone held horizontally; correcting scanned documents that were fed upside-down; adjusting passport/ID photos to correct orientation; making vertical images horizontal for horizontal-preferring layouts.