I have tried to create my own theme to fit in with an existing site I was working on but for some reason the breadcrumb is not displaying the breadcrumb trail in the H2 tags of my site : www.thisismoda.com/gallery .

Is there anything I should check my image.php and album.php files for?

There should be a trail, like in the original theme. You have to include each object, not just one function.

I should make a breadcrumb function, but as of yet it doesn't exist so you need to do that.

Look at how it's done in the default theme, you'll see it.