Trouble!!!

I am having trouble with a few things on the blog, such as the writing. For some reason some of the writing does not take on the automatic style, colour and font in which means it looks different, however when i go to edit the post it seems to be fine so i am puzzled as to what is causing this. To further this i am also having trouble with the size of the video, i have embedded them as the smallest size in which is offered but i still however seem to have the big sized videos on there.another thing in which i cannot work out what has happened with the pictures in which are in the posts as i cannot see them on my computer or the schools main computers? If anyone can help me i would be keen to know so i can make it look better!!! :D