Uploading Photos from cPanel?

Perhaps I’m mistaken about how this all works.

I’m fairly new to WordPress, so excuse my n00bage.

I am using Filezilla as my FTP through HostGator’s cPanel.

My question is: When I’m in my WP Dashboard, and I’m looking to insert a photo into a post, how do I select photos I’ve uploaded to already into cPanel?

So, if I’ve uploaded 3 photos into my wp-content/uploads folder using FTP, how do I select those photos next through WordPress, rather than having to re-upload them through WordPress? Doesn’t that defeat the point of having an FTP to upload files to begin with?

I think I’m just confused. Someone slap some sense into me. Thanks!