There is no doubt that mobile phones, revealing clothing, television sets, and satellite dishes are all from the realm of things, and legal rulings are not connected to things in and of themselves, they are connected, rather, to their usage. Mobile phones, for example, have many beneficial usages, and they is the most noticeable leap forward in the field of communications. There is nothing wrong with increasing the capabilities of these devices by adding video cameras and the like.
People can use video cameras for both permissible and impermissible things, regardless of whether it is attached to a mobile phone or stands alone, and regardless of whether it is large or small. The point is how it is used, because mobile phones or, more precisely, video cameras, have multiple uses: they can be used to reveal what should be kept private and spread loose morals, it can be used to serve Islam and spread beneficial knowledge, or it can be used things that are merely permissible.
Similarly, women who buy revealing clothing can wear it in front of their husbands and still cover themselves in front of strangers, or they can wear it in front of strangers and thereby be committing sin. Similarly, televisions and satellite dishes can be used for cultural and educational purposes, or for that which is forbidden.
It is well established in Islamic law that if the impermisibility of an action is not specified, it is permissible. After enumerating things whose impermisibility was not specified, like horned rams (al-kabsh al-natuh), fighting cocks (al-dik al-muqatil), and pigeons, al-Zayla’i said they were not impermissible, “Because their essences are not reprehensible, but the reprehensibility is in [some of their] uses.”
Based on this it is permissible to sell and trade in anything that has more than one use, and the responsibility falls with the person that will use it; if they use it in a permissible manner, it is permissible, and if they use it in an impermissible manner, it is impermissible and they incur sin.
And God is Most High and Knows best.