Hello there and thank you for submitting this post on InPixio support forum webpage.
InPixio Photo software allows you to connect to your Facebook profile and to upload images to photo album of your choice.
You can’t directly post image to Facebook page that isn’t associated with this sign-in credential.
Alternative way to achieve what you are trying to do is to set the sharing options of this album accordingly, so it can be visible by everybody, just you or selected group of friends.
All the best,
InPixio Support team