I will commit the greatest sin in this thread possible:
I will make a serious post.
You're welcome to skip it if you find it offensive.
What concerns me is the use of the word "offensive".
To my understanding, it is a synonym for "aggression", "attack" and "insult".
That is, describes a direct act, not a passive event.
Something "offensive" has a target that launches out against of.
For example, this whole thread is an act of aggression towards the close-minded people that prefer censorship to self-discipline.
The Merriem-Webster online dictionary has this entry for the word:
Pronunciation:
\ə-ˈfen(t)-siv, especially for 1 ˈä-ˌfen(t)-, ˈȯ-\
Function:
adjective
Date:
circa 1564
1 a: making attack : aggressive b: of, relating to, or designed for attack <offensive weapons> c: of or relating to an attempt to score in a game or contest; also : of or relating to a team in possession of the ball or puck
2: giving painful or unpleasant sensations : nauseous, obnoxious <an offensive odor>
3: causing displeasure or resentment <offensive remarks>
When it comes to non physical acts though, it is usually meant in regards to "insulting", which is also an attack against certain people, either targeted directly or indirectly.
Direct targeting would be for example the famous Danish cartoon of the bomb-headed Muslim Prophet, that angered the Islamic population. That was a direct attack against their religion, baiting their reaction as to bring out the issue of the freedom of speech. The Islamists that protested violently, burned or stepped over the danish flag as a direct offense against the nation of Denmark that originated and protected the source of their anger.
Similarly, if one is to post an image that attacks in one way or another a religion, a nation, a symbol and so on, the term "offensive" is well applied to describe it.
The also famous campaign of the clothing corporation of Benetton aimed to "shock and awe" the consumers with images that were not by themselves insulting or aggressive but their size and persistence in public was difficult to swallow. It followed the rule of advertising that "there is no bad publicity" and was successful as that. As much are depictions of "perfect", scantily-clad women offensive to the feminist ideology.
Usually though, indirect "offensives" are used as a metaphor as in "attacking the senses", to describe something we dislike:
This odor is offensive. This food has an offensive taste. And so on.
Indeed, there are attacks to the senses that are easier to escape than others. Terrible architecture or hundred meter billboards are hard to escape from. Food in prison is hard to escape from. If your workplace or your spouse stinks, that is also hard to escape.
Yet, there are other things that are easy to ignore.
The exhibition of an artist you dislike doesn't have to be visited. Unless you are force to go there with a class.
The taxi cab driver could turn the music down or off. Unless he doesn't have respect for the customer.
Fast Food burghers don't have to be eaten. Unless you can't afford better food.
Anyway, you get my drift.
I fail to see then how a photograph, found on a forum on the Internet, that no one forces you to visit, can be offensive unless it directly attacks your religion, ethnicity, etc. And even then, maybe it is worth discussing, before you respond violently. Hey, maybe Christ was right with that "turn the other cheek" nosense, especially when it is not a physical attack that can harm your health.
Before you substitute the word "offensive" for "disliking" to describe a photograph, think about it well. If it is insulting and can justify the insult, then maybe its worth doing something about. If it is just something you don't like, ignoring it is the best action to take.
(my approach to the subject is shallow and hurried, but I don't have the time to get much more in depth. I hope I get the message across and offend anyone by what I've written or omitted)