of course it’s possible. You just need css and html knowledge.
html:
<div class="youtube">
[youtube embed code]
</div>
css :
.youtube {
background: url('location/your-picture.jpg');
padding: 15px; /*change with number pixel you want*/
}
Does it make any difference if I want to use a Vimeo video?
Is there anywhere in particular i ought to put the css?
I’ve tried just tagging it on the end of the theme’s css but the picture doesn’t show.
There is several ways to custom css.
most simplest is adding in to your theme css.
can you post your website link?