I am new to Mac I have always been a PC user so here I go with my first dumb question. What happens when you re image a MacBook, is it like formatting will I loose everything I have installed?
If you actually image the disk -- i.e. overwrite it from a disk image*/ clone, of course you'll lose everything.
If you are re-installing the OS, you have several options, ranging from keeping the existing user directory and apps to formatting and deleting everything. Go look at the Guides section of MR to see more.