Looking for marker files in a batch script - the example below was for an external backup process, but I'm sure you will get the idea:
@ECHO OFF
IF EXIST D:\XXFLAGXX.TXT GOTO D
IF EXIST E:\XXFLAGXX.TXT GOTO E
IF EXIST F:\XXFLAGXX.TXT GOTO F
IF EXIST G:\XXFLAGXX.TXT GOTO G
IF EXIST H:\XXFLAGXX.TXT GOTO H
IF EXIST I:\XXFLAGXX.TXT GOTO I
IF EXIST J:\XXFLAGXX.TXT GOTO J
IF EXIST K:\XXFLAGXX.TXT GOTO K
IF EXIST L:\XXFLAGXX.TXT GOTO L
IF EXIST M:\XXFLAGXX.TXT GOTO M
IF EXIST N:\XXFLAGXX.TXT GOTO N
IF EXIST O:\XXFLAGXX.TXT GOTO O
IF EXIST P:\XXFLAGXX.TXT GOTO P
IF EXIST Q:\XXFLAGXX.TXT GOTO Q
IF EXIST R:\XXFLAGXX.TXT GOTO R
IF EXIST S:\XXFLAGXX.TXT GOTO S
IF EXIST T:\XXFLAGXX.TXT GOTO T
IF EXIST U:\XXFLAGXX.TXT GOTO U
IF EXIST V:\XXFLAGXX.TXT GOTO V
IF EXIST W:\XXFLAGXX.TXT GOTO W
IF EXIST X:\XXFLAGXX.TXT GOTO X
IF EXIST Y:\XXFLAGXX.TXT GOTO Y
IF EXIST Z:\XXFLAGXX.TXT GOTO Z
ECHO EXTERNAL DEVICE NOT FOUND - BACKUP PROCESS ABORTED!
GOTO END
:D
D:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "D:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:E
E:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "E:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:F
F:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "F:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:G
G:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "G:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:H
H:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "H:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:I
I:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "I:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:J
J:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "J:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:K
K:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "K:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:L
L:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "L:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:M
M:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "M:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:N
N:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "N:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:O
O:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "O:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:P
P:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "P:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:Q
Q:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "Q:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:R
R:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "R:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:S
S:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "S:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:T
T:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "T:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:U
U:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "U:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:V
V:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "V:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:W
W:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "W:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:X
X:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "X:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:Y
Y:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "Y:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:Z
Z:
CD\
CD ROBOCOPY
ROBOCOPY "C:\Users\Sarah" "Z:\Sarah" /E /PURGE /xd "System Volume Information" /xd Recycler /xd Recycled /R:0 /W:0
GOTO END
:END
ECHO.
ECHO.
ECHO PRESS ANY KEY TO CONTINUE
PAUSE
When it comes to multiple images and multiple models, you can use WMI under WinPE to detect the chassis and choose the appropriate image from your library. You can make it as automatic as you want, or alternatively build an HTA based GUI that runs under WinPE, and can give the technician a number of choices.