Featured Images not showing up (WITH theme support)

Hi everyone,

Before we switched themes, we were already utilizing the featured image functionality. We got a new theme (Santiago) and the featured images aren’t being pulled up on single posts. Theme support for thumbnails exists in the functions.php and everything else (like related posts plugins and widgets) recognize the featured images. I checked the templates and it’s in there… I don’t understand why it’s not recognizing it? I triple checked theme options to make sure it wasn’t just a setting, but i’m so beyond me reach here. Can anyone help?

Also, I seem to be the only one with this problem. I deactivated my plugins to see if it was a conflict but didn’t see any difference. This is what the single content calls for

<?php
			$show_feat_img = get_post_meta($post->ID, 'fp_meta_post_add_featimg', true); 

			if ($show_feat_img == 1){ ?>
				<div class="entry-image">
					<?php the_post_thumbnail( 'fp770_375' ); ?>
				</div>
			<?php
			}

Can anyone help?