The disk images for the operating systems are sparse, i.e. they expand as necessary. They unfortunately do not shrink automatically when you delete data.
For a windows image you have to install the VMware tools to shrink the disk.
The VMware Tools are installed by: Start your virtual Operating system -> Move mouse to the top of the screen and select 'Virtual Machine' -> 'Install VMware Tools'
VMware Tools location
C:\Program Files\VMware\VMware Tools\VMwareControlPanel