Yes, from this page click the '+' sign next to Free Pictures, then press 'Edit Pictures'. This is where you will be given the option to move an image to your Private Gallery.
If you wish to include images on your main profile, you will need to add these manually here.
Note:
Please refrain from duplicating free content in your Private Gallery as that may be viewed as deceitful and could result in member(s) being refunded or these images being removed on your behalf.