How do I number the lines in a text file using a batch file?

talk random
1

I basically want to change:

 C:\images\fdsfads.jpg
 C:\images\gdsf.jpg
 C:\images\dsfasdfds.jpg
 C:\images\fgsdfgdsf.jpg
 C:\images\dsfgdsgdf.jpg
 C:\images\dsfadsd.jpg
 C:\images\fgfdgsdff.jpg
 C:\images\ghfghrrth.jpg
 C:\images\jhgjhhghjf.jpg

to

 1=C:\images\fdsfads.jpg
 2=C:\images\gdsf.jpg
 3=C:\images\dsfasdfds.jpg
 4=C:\images\fgsdfgdsf.jpg
 5=C:\images\dsfgdsgdf.jpg
etc

Many thanks,
Mike