Georeferencing - jpg does not appear in Layer dropdown menu

[DougWolfinger2]

I am trying to georeference a jpg image of a map in ArcMap 9.3. Here's the process:
I add the spatially referenced data first, then add the jpg raster. The lon/lat coordinates are still correct at this point.
But the jpg is not in the view yet because the view is zoomed out to the full extent. The vector is global data of Mars, and the jpg map is just one small region.

So I click Zoom to Layer to make the jpg appear. It appears, but this is when the lon/lat coordinates are thrown way off. For instance, in decimal degrees, lon=20E, lat=20N will become something like lon=0.00136, lat=0.002302.

I want to zoom into the jpg and use Fit To Display on the vector to get the two to be about the same proportions in the data view before I start setting control points. What am I doing wrong? Thanks!

[DougWolfinger2]

I think I had that backwards; I need to do Zoom to Layer on the referenced vector, then Fit to Display on the jpg raster. But I can't do Fit to Display on the raster because it does not appear in the Georeferencing Layer dropdown menu. So that's what the problem is. The lon/lat coordinates get messed up if I Zoom to Layer on the raster, but they're fine after I Zoom to Layer on the vector.

How can I get the jpg to appear in the Georeferencing Layer dropdown menu?

[DougWolfinger2]

Just fyi, I solved it. The raster jpg I was using just wasn't loading into the Georeferencing Layer menu for some reason. Every other jpg I tried, loaded into that menu, so I made another jpg copy of the map I needed, added it to the data view, and it appeared in the Georef Layer drop-down menu.