small programming question

[Claude Jones]

Could someone help. I have chosen a bad naming convention for a long list, and 
I need to make a small alteration. The list looks like the following
001-Fig 1-1.jpg   
013-Fig 4-4a.jpg  
024-Fig 5-6.jpg   
035-Fig 5-17.jpg
etc...
I would like to add a 0 to each group of three numbers at the beginning of 
each name so that 001-Fig 1-1.jpg becomes 0010-Fig 1--1.jpg for example.
Could someone help me with the quick way to do this? 
-- 
Claude Jones
Bluemont, VA, USA