How can I have two different size fonts in the page title / heading?

hard to say without a url to site – or at least theme name

sorry – I can’t get it – looks like the author is not supporting or letting you down load it

if you can get to the code that shows the post title (in single.php or index.php) you could try and edit it:

instead of what it is likely to be:
<h3 class="post-title"><?php the_title(); ?></h3>

you could try and use:
<h3 class="post-title"><?php the_title(); if(is_single('3d')) { echo '<span> - click any thumbnail to view</span>'; } ; ?></h3>

add to style.css:
h3.post-title span { font-size: 70%; }

and then set the page name and slug of your post to ‘3D’ and ‘3d’ resp.

@dmattock
you probably edited the wrong file.

there would have been no permalink code around the code that i suggested to be replaced.
i don’t know your file system, so i assume that this should be in single.php (?)

and you can use capital letters in the post name, as wordpress will convert it into the slug to use in permalinks.

the problem could be that this is not single.php, so the if(is_single('3d') might fail to work.

you could try to use the post id instead:

<h3 class="post-title"><?php the_title(); $postid=$post->ID; if($postid == 88) { echo '<span> - click any thumbnail to view</span>'; } ; ?></h3>

‘motion graphics’ would be postid = 18
coudn’t find ‘illustration’ (is that ‘2D’ ? that would be postid = 89)

as long as these posts are shown with ‘page-nosidebar.php’, then the following might work:

<h3 class="post-title"><?php the_title(); $postid=$post->ID; if( $postid == 88 || $postid == 18 ) { echo '<span> - click any thumbnail to view</span>'; } ; ?></h3>

the || stand for logical or

if ‘illustration’ is indeed ‘2D’ then the code would be:
<h3 class="post-title"><?php the_title(); $postid=$post->ID; if( $postid == 88 || $postid == 18 || $postid == 89) { echo '<span> - click any thumbnail to view</span>'; } ; ?></h3>

i use firefox and the web developer add-on; when i tick the ‘css – view style information’ setting, i can hover over the page and see a lot of class and id information.
as some themes add the post-id as a css identifier to the post container, i can get this information easily.

you could go into ‘admin’ ‘posts’ and the hover over the post title in the list – you should then see the permalink in the browser link window at the bottom left of your browser with the post-id at the end.

another way is to look at the html fof your page from the browser:
click ‘view’ ‘page source’ or ‘ctrl U’ in firefox for instance. this gives you the total html that builds your page. then go through the code until you find the title of your post, for instance:
here is a copy of a bit from the html code of the 3D post:

<div id="#content-left-nosidebar">

			<div id="post-88" class="post-88 page hentry category-uncategorized">
				<h3 class="post-title">3D<span> - click any thumbnail to view</span></h3>