If you backup your iPhone using iTunes, is it a full backup even if on the iCloud settings it's not? I only have 5 GB of iCloud storage. So my iCloud backup settings on my iPhone, i didn't include Photos (cause I have 6 GB worth of photos).

Now if I wanna do a full backup of my iPhone, does the manually backup option on iTunes work?

Will it be a full backup? I checked the backup size on my Mac and it says 7 GB, so is it safe to assume that it was a full backup?
It is "full" in the sense that everything that is ACTUALLY on your device is backed up (minus payment and password/security settings for obvious security reasons), but it is NOT full in the sense that not everything you see on your device is truly "on" your device. Some stuff is merely just a shortcut (for the sake of a longer explanation) to items stored in iCloud.  The details and differences of iCloud and iTunes -based backups, along with what is excluded (such as those shortcuts) in an iTunes backup are documented here, courtesy of Apple, on their support site.