Understanding vertical-align

Title (and content) of the article I stole from this web site.

From that same web site copy / paste of the key sentence:

HTML layout traditionally was not designed to specify vertical behavior

To have properly working vertical alignment, in my case, I had to introduce a table, this is my HTML:

<div style="height: 800px" class="detail-control">

	<table style="height:100%">
		<tbody>
			<tr>
				<td>
					<img style="vertical-align: middle" border="0" alt="Please press the play button." onerror="this.src='path to image to be displayed if original one is not found'" src="/URL of an image">
				</td>
			</tr>
		</tbody>
	</table>

</div>

Notice height of div (800px for the sake of testing), and height of table (100% to cover whole div), then in img tag note style.