Scaling One Dimension of UV Image

I can’t seem to figure out the scaling part of Blender’s UV image editor. If I want to scale it, it looks like it must be in both dimensions. Why can’t I simply stretch the image in one dimension?

Hit S to Scale, and then then X or Y for the X or Y axis.
Have fun!

keep in mind that only selected UVs are scaled.

Also keep in mind that since UVs are two dimensional, y is up and down, x is left and right.

Also also keep in mind that other hotkeys work with the UV map as well. I.e. r=rotate, g=grab. If you didn’t already know that.