Who do you think is responsible for your security when you surf the Web? The answer to this question is rather simple: you are responsible for it. Not the government, not your family nor your antivirus seller. Only you are fully responsible for your Internet security while you spend time online.
It might feel natural to want to share pictures on the Internet with others together with many other files that others want to share with us. One problem with sharing files is that some nasty viruses can hide in them and they can completely ruin your computer when it comes to its security. My advice here is to be very careful what types of files you open.