Before & after
panorama viewer
A split-view viewer for equirectangular panoramas. Load two 360° images, drag the divider across the same scene for a before-and-after, and rotate the second until it lines up with the first. Nothing is uploaded — the panoramas never leave your machine.
How to use it
- 01
Load a panorama
Drag an equirectangular JPEG, PNG or WebP onto the viewer, or press Load. Drag inside the image to look around, scroll or pinch to zoom.
- 02
Load a second one
Drop a second panorama into slot B. The view splits in two and a divider appears between them.
- 03
Drag the divider
Sweep the divider across the scene for a before-and-after. Both halves share one camera, so panning and zooming move them together and the seam always matches.
- 04
Align the second panorama
Two captures rarely share a heading. Press Drag to align B, or use the slider, until the right half lines up with the left. Arrow keys nudge it a quarter degree at a time.
What it's for
- Comparing two reconstruction or stitching pipelines on the same capture
- Before and after on denoising, HDR merging, upscaling or inpainting
- Checking an on-device render against a backend or desktop one
- Renovation and site-progress shots taken from the same spot
Questions
What is an equirectangular panorama?
A full 360° × 180° view stored as a flat 2:1 image — the format a 360 camera, a phone panorama app or a photogrammetry pipeline exports. If your image isn't exactly 2:1, the viewer resamples it so the projection stays correct.
Are my panoramas uploaded anywhere?
No. The file is decoded by your browser and handed straight to the GPU as a texture. There is no server, no account and no upload — the page works with your network disconnected once it has loaded.
Which file formats work?
Anything your browser can decode: JPEG, PNG and WebP all work, at any resolution. Large panoramas are resampled to fit the GPU's texture limit.
Why don't my two panoramas line up?
Because they were almost certainly captured from a different heading, even when shot from the same spot. That's what the alignment control is for: it rotates the second panorama around the vertical axis until its features match the first.
Does it work on a phone?
Yes. Drag with one finger to look around, pinch to zoom, and drag the divider to compare. Panoramas are loaded at a smaller texture size on small screens to stay within memory.
Is it free?
Yes, and there is nothing to sign up for.
Built while working on phone-captured spatial reconstruction — the two panoramas it opens with are the same room rebuilt by two different pipelines. More tools.