If you are going on Facebook via your phone, then you might be able to upload directly from your phone, I don't know.
If you have a USB cable, then plug it into the computer. Look in My Computer, and you'll see your hard drive (C:), a DVD drive probably (D:) and then you will probably see an E: or F: drive that will say "removable drive" or even "LG Cosmos". If you double click on that drive, you may then see folders, hopefully something obvious like "photos", and you can copy the photos off and onto your computer. You'll have to try it as I don't have an LG phone to try it out.