Aligning Images Vertically

I'm new to web design, and I'm having some trouble positioning images in Microsoft Expression Web. My goal is to vertically align the two smaller images (red and green) shown in the attached image, and have them directly to the right of the larger image (blue). These are placeholder images. The smaller images simply refuse to be aligned and directly to the right of the larger image. What is the next step I need to take? I see many similar questions online, but the examples have not worked for me.

Forgive me if my terminology is incorrect; I'm a novice. I appreciate any advice the community can offer.Example 1