problem on my site, if we upload anything in backend ,there is a problem in home. all home page images are not shown,it showing blank

i purchased kutetheme For my site www.firstwordsbooks.com..if i make any changes in backend my theme Home page is getting problem . is i have to purchase visual composer. i purchased only theme. but whenever update there is a problem . please find my problem and give solution .
client getting tense
pls contact me immediately