Main Image on page

i’ve loaded image in 2 pages throw the main image while aditing page.
i can see it in the edit mode, however, when i do the preview, i don’t see it.
i used the code:
.page .entry-title {display: none;} in the custom css to block the page title from the body, but it seems that’s not the problem. couse i tryed removing it, and it still didn’t work.