What Are Lightroom Smart Previews? A Wedding Photographer's Guide
If you have ever tried to send a wedding off for editing, or move your catalog between two computers, you have run into Smart Previews. Lightroom offers them at import, buries them in a checkbox, and never really explains what they are. So here is the plain version, written for photographers, not engineers.
What a Smart Preview actually is
A Smart Preview is a lightweight stand-in for your original photo. When you build one, Lightroom creates a compressed DNG copy, capped at around 2,560 pixels on the long edge, and stores it next to your catalog. It is small, a fraction of the size of your full RAW file. But it carries enough real image data that you can cull, colour, and edit against it as if the original were right there.
Think of it as a working proxy. The full-resolution RAW stays exactly where it is, on your drive. The Smart Preview is the version your edits actually happen on, until the originals are reconnected and every change applies back to them at full quality.
Why they exist
Two reasons, mostly. The first is portability: you can unplug your external drive, leave the originals at home, and keep editing on a laptop at a cafe, because the Smart Previews travel inside the catalog. The second is size. A full wedding of RAW files can run to hundreds of gigabytes. The Smart Previews for the same wedding are a small enough package to actually send somewhere without a courier.
The original never leaves your drive. The Smart Preview is the part that travels, and it carries enough to edit on without losing a thing.
Why they matter if you outsource
This is the quiet reason Smart Previews are a wedding photographer's best friend. If you want someone else to edit a gallery, you do not want to upload 400GB of RAW files. You build Smart Previews, export the catalog with them, and share a package that is a tiny fraction of the size, while every original stays safe and untouched at home. The editor works on the previews, and the edits map straight back to your full-resolution files when you reconnect them.
That is exactly how editing with Selects works: you send Smart Previews plus your catalog, we edit against them, and your originals never leave your possession. Here is the full flow.
How to build them
You have two moments to do it. At import, tick "Build Smart Previews" in the File Handling panel and Lightroom makes them as it ingests. Or after the fact, select your photos in the Library module and go to Library, then Previews, then Build Smart Previews. Either way your originals are not altered, and a small badge under the histogram confirms a Smart Preview exists for a given image.
One habit worth keeping: build them before you rename or reorganise folders, and do not move files around afterwards, because that can break the link between the catalog and the originals. Build first, reorganise never.
Once you have the hang of Smart Previews, packaging a wedding for editing stops being a chore. Here is the full step-by-step for preparing your catalog, so the handoff takes ten minutes instead of an evening.
