I'm trying to understand the differences between LR and Bridge. I understand that when you import into LR, you are not really pulling the images themselves in, but the data of the images (?). So, if I do all my editing to my raw files, and then export to, say, PSD's, can I delete my original raw files from my hard drive, or will I lose the information that the catalog is using within LR?

I just confused myself thoroughly. Hopefully someone out there can explain it to me.

My biggest problem is that when I am trying to export to PSD, i am running out of hard drive space on my MBP. Can I delete the raw files and still come back to the catalog in LR if I need to do stuff later on?

LR allows you to do several things, including:

1) Import: just another way of saying let LR keep track of things for you.

2) Copy: actually copy your image files to another place on your computer. Which you can do without LR.

3) Edit/Develop: Well, actually, you're altering settings in LR that relate to a particular image or set of images. You're not really editing the actual image files. You're creating "looks" for your images and the settings for those looks are stored separately. You can "apply" those looks to your images when you export the images.

4) Export: this is where you tell LR to apply any settings to an image and copy the altered image to another place on your computer. The original image file (usually RAW) is left alone.

Note that LR doesn't store your images, your computer does (on a HD or some other media). So, deleting images in LR usually mans deleting references to images, not actual images. Unless you tell LR to delete the actual images (the RAWs). In any event, deleting your RAW files is deleting your RAW files. They will no longer exist, and LR can't do anything with them, or bring them back. Not deleting them means they exist and thus take up space.