Vertices are pink squares instead of yellow dots

I am modeling an object using background images. When I select a vertex it turns into a small pink square big enough to block out some of the surrounding area so I can’t see exactly where my vertex is at. They used to be nice yellow dots and I could see exactly where they were.

If I create a vertex, though, and then create a connected one using Ctrl-LMB then move the new one, it is a small yellow dot like it should be, but if I select an already existent vertex and try to move it, it is the pink square.

What’s going on and how do I get them back to nice yellow dots?

I am using Blender 2.45.

Maybe check
User preferences —> themes ----> 3D view ----> vertex size ( I think default is 3)

It’s the new Active Vertex thing. You’ll notice the last line you selected also turns pink. My solution: Go to the same place as vertex size, and pick “Active Vertex/Edge/Face” and set it to a pale blue with around 50 alpha, which is good enough to see on all the things without being that noticeable on verts.