Lightroom is an inherently non-destructive program, meaning Lightroom does not change the pixels in your original photo file. Your edits are stored in the Lightroom catalog as a set of instructions, like a recipe card. When you access an image in Lightroom, Lightroom follows the path to where the photo file is stored on your computer, reads its history of your edits, and quickly renders an image on your screen that reflects your edits. To expedite this process, Lightroom creates small "preview" files for its use behind the scenes. But, there is no full-sized photo file with your edits until you export from the library or use an output option in the other modules.
For example, if you need to send an edited photo to a lab for printing, you would use the export dialog to create a new JPEG or TIFF (or whatever the lab specifies) that reflects all your edits. You would then send that new file to the lab, while your original raw file remains intact and untouched.
I would be delighted to work with you to build a streamlined workflow and backup strategy, and gain confidence and ease with Lightroom. I hope to hear from you soon!
