Help! I've clicked and I can't get it right

Ok so I don't really know what I'm doing with this blog.  I've clicked to add a picture and now I realize its too big and can't remember how to get to the same place to change things.  This is all a little confusing to me.  I've read other blogs that tell how to customize things but I didn't really pay that much attention.  I was on their blog to check out their crafts and photos they had.  If I'm going to get any followers I'm going to need to figure this out.  Please bear with me on this. thanks, Aunt Kadra Louise