large featured image size

See https://codex.www.ads-software.com/Function_Reference/the_post_thumbnail

that seemed to help, putting ‘thumbnail’ and ‘full’ in the php.

but why is the image so far above the div?
i can’t get it to move down, even with margins.

Try using Firefox with the Firebug add-on for this kind of CSS work.
https://getfirebug.com/

I tried using firebug, didn’t seem to help me.

See this in style.css line 436:

img.wp-post-image {
    float: left;
    height: 223px;
    margin-left: 250px;
    margin-top: -267.5px;
    padding-left: 10px;
    width: 396px;
}

I still can’t seem to ge the thumb to display at full size (825×500).
I inserted this code to call image and put in a div to help style in css.
`<div class=”post_imageLRG”>
<a href=”https://www.youtube.com/v/&lt;?php echo get_post_meta($post->ID, “youtube_url”, true); ?>/”><?php the_post_thumbnail(‘full’); ?></a></div>`

i got it lowered, but it doesn’t seem to be showing the image at full size, it’s at standard thumb size.

When I tried changing the height and width in the above CSS code, it changed the size on the page — did you try that?