All i want to do is scale an image vertically I want to scale a background image vertically so it matches my object height, (it's a 2d side view).

I have the length correct but was hoping for something easy like corner boxes like in Photoshop so I can stretch the image vertically.

I don't want to move it around / offset it but want to stretch it down but the top stays in the same position.

Using blender 2.79.
If you introduce a reference using the 'Background Image' mechanism, I'm fairly sure you can't scale it non-uniformly, or about a chosen origin.

You can, though, by introducing the image as an object, either by creating an  'Image' Empty, or by importing 'Images as Planes'. In both cases you could snap the cursor to your desired stationary point on the model (Edit Mode, ShiftS, > Cursor to Selected), then switch to the image, and, say, SY, with the Pivot Center set to the cursor.