How Edits Are Saved
A pain point for newcomers to Lightroom has been the question of how to save images. In your very first computer lesson, you probably learned how important it is to save your work before you close a program. Lightroom 1.0 perplexed a lot of people because there was no "save" menu item; users were left wondering if they would lose all their work after they quit Lightroom. Of course you realize soon after you start using the program that your work is saved automatically. Even if Lightroom suffers a crash or there’s a power failure, you shouldn’t lose all your work.
Lightroom 1.1 ends the confusion by including a Save Metadata to Files command in the Library module’s Metadata menu. This command forces an export of the metadata information from the Lightroom internal catalog to the actual image file.
It’s important to remember that as you do any kind of work in Lightroom (adjusting the Develop settings, applying a color label or star rating, editing keywords or other metadata), your edits are stored in a central Lightroom catalog on your hard disk. For simplicity’s sake, we can summarize these changes by grouping them under the term metadata edits. When you do anything to an image in Lightroom, you’re not changing the fundamental structure of the image; instead, the whole concept of Lightroom is built around the idea that the imported images are the master negatives, and Lightroom records any changes as metadata information that’s always stored separately from the image data.