Image Side-by-Side Combiner
Combine two images horizontally or vertically into one.
Overview
The Image Side-by-Side Combiner joins two uploaded images into a single output, placed either horizontally next to each other or vertically stacked. Configure the gap between them, pick a background colour for any letterboxing, and the tool returns a re-encoded composite ready for download.
It is the right tool for before/after comparisons, social-media carousels condensed into one frame, recipe screenshots paired with the dish photo, or any time two images belong together but you only have one upload slot. Designers also use it to assemble quick comparison shots for client review without launching a layout app.
How it works
For a horizontal join the tool measures both inputs, sets the output height to the taller of the two (or to a user-specified value), and pads the shorter image vertically with the background colour. The output width is the sum of the two image widths plus the gap. The vertical join works symmetrically — output width matches the wider input and the heights are stacked plus a gap.
Each source image is blitted into its allocated half of the canvas without resampling — pixels are copied byte-for-byte. If the two images differ in aspect ratio the user can opt for a centred placement (default) or for top/left alignment. The encoder writes the composite in PNG by default to keep alpha, or in JPEG if you need a smaller file.
Examples
Before: before.jpg (800x600) + after.jpg (800x600), horizontal, 10 px gap
After: 1610x600 side-by-side composite
Before: cover.jpg + table-of-contents.png, vertical, 20 px gap
After: stacked composite suitable for an Instagram carousel
Before: desktop screenshot (1920x1080) + mobile screenshot (390x844),
horizontal, centred vertically
After: 2310x1080 image with the mobile shot framed by background
FAQ
Can I combine more than two images?
This tool handles pairs. Chain the output through it twice (combine A+B, then combine that result with C) to assemble triptychs and longer strips.
Will the images be resized to match?
No — they are pasted at their native resolution and padded with the background colour where heights or widths differ. Resize first using the Image Resizer if you want exact alignment.
Does the gap support transparency?
Yes for PNG and WebP output — set the background to fully transparent. JPEG output flattens to white.
Is there a label option?
Not in this tool. Combine the output with the Image Watermarker if you need a "Before" / "After" caption.
Can I align left/top instead of centred?
Yes — the alignment option lets you anchor the smaller image to a corner instead of centring it in its allocated half.