Hello Keith,
I may be over simplifying your inquiry but couldn't you go to the image in the MXD, right click > Properties, make note of the source path. Then open Pro and in an active layout go to the Insert tab > Graphics and Text group > and click the Picture icon. Then when the Insert Picture pane appears enter that source path you collected before and add the image that way?
Like I said I may be over simplifying your inquiry and if so, please clarify further on what exactly your looking to do.
I hope this helps!