This is one of those times where I wish I could see how many points your comment got.
I don't know whether you've gotten a lot of votes or not so I don't know if your answer makes sense to other people as well.
Why do you think you don't need permission to take pictures of a country from space?
I think there are certain areas in all countries that they would want to keep secret, and if you allow people to photograph in certain areas and not in others, that's exposing where these areas are (which is an invitation for governments to spy on those areas).
Why does it matter how many points my comment got?
But, the closest I could get:
UN General Assembly, resolution 41/65, of 3 December 1986: Principles Relating to Remote Sensing of the Earth from Outer Space.
Principle IV: These activities shall be conducted on the basis of respect for the principle of full and permanent sovereignty of all States and peoples over their own wealth and natural resources, with due regard to the rights and interests, in accordance with international law, of other States and entities under their jurisdiction. Such activities shall not be conducted in a manner detrimental to the legitimate rights and interests of the sensed State.
I'm not sure how remote sensing could violate jurisdiction over wealth and resources, but it does not mention territory.
And then there's principle XII: As soon as the primary data and the processed data concerning the territory under its jurisdiction are produced, the sensed State shall have access to them on a non-discriminatory basis and on reasonable cost terms. The sensed State shall also have access to the available analysed information concerning the territory under its jurisdiction in the possession of any State participating in remote sensing activities on the same basis and terms, taking particularly into account the needs and interests of the developing countries.
If prior permission to perform the sensing was required, provisions stipulating that the data should be shared would be redundant, I think?
Although international law doesn't spell it out verbatim, the generally accepted principle is that sovereignty does not extend to the altitude where satellites fly. As such, it's impossible to prevent anyone from taking pictures of any country from space.
