My In-Laws Are Always Showing Off Their Vacation?

My in-laws (parents in law and one of my sister in law) are always talking about their vacation, every time they go on vacation. They would write emails, show pics, postcards about it. I know there is nothing wrong with talking about where you traveled too but it is way too much and it's annoying too. But since they are well off, that's the only thing they mostly talk about. that and their family. Sometimes it is annoying because my family and I can't afford to go traveling all the time, maybe once a year. We work and have a family to raise and we are not rich. Even if we did go on vacation, we hardly show pics and talk about it with others who are less fortunate than we are. I think it would be nice for my in laws to go do some volunteer work and talk about that instead of their vacations, I would appreciate and respect them more. Am I selfish? I know there is no polite way to tell them to quit showing off their vacation pics.