Basic PHP question (displaying post title over thumbnail) [closed]

You don’t need php at all to achieve what you are after.
This can be done with just css.

This shows the title and excerpt by default.

.wrap .wp-tiles-byline-fade-in .wp-tiles-tile-with-image .wp-tiles-byline {
    opacity: 1;
}

This hides the excerpt again now that we have revealed it.

.wrap .wp-tiles-byline-fade-in .wp-tiles-tile-with-image .wp-tiles-byline .wp-tiles-byline-content {
    opacity: 0;
}

And this shows the excerpt again when you hover over it.

.wrap .wp-tiles-byline-fade-in .wp-tiles-tile-with-image:hover .wp-tiles-byline .wp-tiles-byline-content {
    opacity: 1;
}