I am used to http://www.wordpress.com, and when i add a picture in the blogg post it automaticly resizes itself to fit.
Like this: http://teigas.wordpress.com/

But since i now have converted to wordpress.org and started to test adding posts and pictures, there is a problem that pictures do not resize automaticly , so if i where to add a long panorama shot, the shot will be on the whole page, over the right widget bar and further.
The blogg on wordpress.org is : http://www.teigen.be/blogg

Is there no such function in wordpress.org? Do i have to resize or drag them to fit?
Is there any plugins ? Any recomendations?