Is it possible to set maximum size limit for the images or document?
Yes but in generally. You can set the maximum limit of any kind of document or picture for the whole website. It is not possible to define document or image separately. It is also not possible to define max limit only for specific sub sites/pages regions separately.
You have to go to Web Application general Settings to set the maximum upload size in general navigating the following path from the central administration panel and set the max size in megabyte.
Central Administration > Application Management > Web Application General Settings
A good article on that:
http://blogs.msdn.com/joelo/archive/2007/06/27/file-name-length-size-and-invalid-character-restrictions-and-recommendations.aspx