Merge Images

How to Merge Images

Features

Combining Photos Without a Design Tool

An image merger combines two or more separate image files into a single output image, placing them next to each other in a row or stacking them in a column — rather than layering them on top of one another. It's the tool you reach for when you have several related photos or screenshots that make more sense viewed together as one image than as separate files: a before/after pair, a set of product angles, a strip of screenshots showing a step-by-step process, or several chat messages that need to be shared as one piece.

This is different from a photo collage, which typically arranges images into a decorative grid with templates and creative layouts — if that's what you're after, the Photo Collage Maker is the better fit. Merge Images is the more precise, utilitarian tool: exact control over direction, sizing, spacing, and order, with a live preview so you know exactly what you'll get before downloading.

How the Merge Works Technically

Each source image is first drawn onto its own canvas, with any rotation you applied baked directly into the pixels — the canvas is resized to swap width and height for 90° or 270° turns, then the image is drawn in after a matching rotation of the drawing context. Once every image has its rotation applied, the tool calculates how each one should be scaled based on your Size Matching choice — to the largest image's height (for horizontal) or width (for vertical), to the smallest, or not at all — always preserving each image's original aspect ratio so nothing looks stretched or squashed.

A single output canvas is then sized to fit every resized image in sequence, plus the spacing between them and the outer border around the whole result — each added independently, only if its own toggle is on — and each image is drawn onto it at its calculated position. If you chose "Keep Original Sizes" and your images have different heights (or widths, for vertical merges), any resulting gap is centered and filled with your border color, or with white if you're exporting to JPG or BMP — both formats lack an alpha channel, so transparent gaps aren't possible in those formats.

Who Actually Needs to Combine Photos

Online sellers and marketers combining multiple product angle photos into a single listing image, or joining a before/after pair for an ad.

Students and professionals stitching a series of screenshots — a multi-step tutorial, a long chat conversation, or a scrolling web page — into one shareable image instead of several separate files.

Designers and social media managers preparing side-by-side comparison graphics, Instagram carousels flattened into one preview, or quote cards that combine a photo with a text panel.

Anyone documenting a process — customer support agents merging a sequence of error-message screenshots, or reviewers merging several photos of a product defect into one image for a claim or report.

From a Before/After Comparison to a Collage

Before-and-after comparison: You have two photos — one before a renovation, one after — and want a single image showing both. Upload both, set Direction to Horizontal, Size Matching to "Match Largest Image" so neither photo loses resolution, optionally add a thin white border to separate them, and merge. The result is a clean side-by-side comparison ready to share.

Stitching a tutorial into one image: You've taken 5 screenshots showing steps in a process and want to share them as a single scrollable strip instead of 5 separate attachments. Upload all 5, drag them into the correct step order, set Direction to Vertical, and merge — the numbered badges on each thumbnail make it easy to confirm the sequence is correct before you commit.

Combining product photos for a marketplace listing: A marketplace only accepts one image per listing slot, but you have 3 angles of the same product. Merge them horizontally with "Match Smallest Image" to keep the combined file size reasonable, add a border for visual separation between angles, and export as JPG for maximum compatibility with the marketplace's upload form.

Every Merge Happens Right on Your Device

Because the entire merge — resizing, rotation, compositing, and export — happens inside your browser using the Canvas API, your image files are never transmitted to a server. For personal photos, unreleased product shots, or screenshots containing sensitive information, this is a meaningful difference: there's no upload step to intercept and no server-side copy left behind. It's also faster for most batches, since there's no upload/download round trip — only a local render that updates the live preview instantly as you adjust settings.

Getting a Clean, Aligned Result

• Use "Match Largest Image" by default — it's the safest choice since no image ever loses resolution, and it's the current default for that reason.
• Rotate before you reorder — fixing a sideways photo first makes it much easier to judge how the final sequence will look in the live preview.
• Add thin spacing for comparison images — even a 6–10px gap between images makes the seam between two similar-looking photos much easier to see at a glance, without adding an outer frame you don't need.
• Choose PNG or WebP if any image has transparency — JPG and BMP will fill transparent areas white, which can look wrong on a logo or icon with a transparent background.
• Check the live preview before merging — every setting change updates it instantly, so you can catch an ordering or sizing mistake before generating the final file.
• Resize after merging if you need exact dimensions — use the Image Resizer on the downloaded result for a precise pixel size.
• Use Copy to Clipboard for quick pastes — when you just need to drop the merged image into a Slack message, email, or doc, copying skips the download-then-attach steps entirely.

Why a Merge Might Look Misaligned

The merged image looks uneven, with some photos much bigger than others. You likely have "Keep Original Sizes" selected under Size Matching. Switch to "Match Largest Image" or "Match Smallest Image" so every image is scaled to a consistent height (horizontal) or width (vertical) before joining.

The images merged in the wrong order. Drag the thumbnails in the strip to reorder them — the number badge on each thumbnail always reflects the current merge order, so you can confirm the sequence before clicking Merge.

There's an unexpected white bar where I expected transparency. This happens when exporting to JPG or BMP, neither of which supports transparency — any transparent source pixels or letterbox gaps are filled white automatically. Switch the output format to PNG or WebP to preserve transparency.

One image appears sideways in the result. Use that image's Rotate button in the thumbnail strip before merging — rotation is per-image and must be set before you click Merge, since the merge bakes the current rotation into the final pixels.

"Copy to Clipboard" shows an error instead of copying. This means your browser doesn't support clipboard image writes, or the page isn't running over HTTPS (the Clipboard API requires a secure context). Modern Chrome, Edge, Firefox, and Safari all support it — if you're on an older or less common browser, use the Download button instead.

What Merging Can't Replace

Don't use this tool if you need a decorative grid layout with templates, frames, or artistic arrangements — that's what the Photo Collage Maker is built for. Merge Images only joins images in a single row or column.

Don't use it if you need images layered on top of each other with transparency or blending — this tool places images next to one another, not on top of one another. For overlaying one image on another, you'll need a layer-based editor.

Don't rely on it for print-ready output requiring CMYK color profiles or embedded ICC metadata — canvas-based compositing works in the browser's RGB color space and doesn't preserve print-specific color management data.

Frequently Asked Questions