You must have extracted those from a UnitXX.spr. You probably shouldn't mess with those unless you want to create fully animated units. The UnitXX.spr sprite files contain the graphics for the unit animations. Each unit has its own sprite file.
To create a static unit with 5+3 orientations you need to use the "Static.spr". That file contains the static images with the 5 facing directions for all units. Export all images from the static.spr, find the 5 images of the unit(s) you want to replace, overwrite them with your own graphics, and import everything again.