Georeferencing Photos With No Spatial Reference?

Knowing the position of the camera, relative to the ground, and assuming the ground to be flat, it should be possible to create target control points at each of the four corners of the image. Then pass those control points to the Warp tool. The source control points would be found by examining the unprojected extent of the image.

To use a higher order transformation, I think you'll need additional control points at interior points, thereby adjusting the scale of the image in the middle more than near the edges.

Warp is useful when the raster requires a systematic geometric correction that can be modeled with a polynomial.

Update

If you just want a quick and dirty approach, then you might be better off building a world file for each photo, by adding an offset to the mid point (assuming that's where your GPS point falls) to describe the corner of the photo, and a pixel size in the linear units of whatever projection you're using.