Hard drive space needed

Question

I bought an external drive to keep all of my docs, photos and videos. I thought that would free up space to do a defragment and it is telling me I only have 1% of space can not defragment.

How can I free up space on the hard drive without deleting something important. I don't know enough about computers.

If I delete all of the photos on my Adobe Photoshop Album, will that free up space in my hard drive? I have approx. 2500 items in the Album.