Slow connection or slow blog?

I’ve recentlly noticed that my blog page is loading very slow and even editing posts takes an unusual ammount of time to complete, what can be? I’m using photos on my posts and I’ve set up couple of pages as well.
My blog is hosted on my web hosting package and I’ve installed in https://www.mywebsite.com/blog
Should I clean my database or what to get it working properly?