There's no way to do this in Photoshop as far as I can tell.
This is however possible in Adobe Bridge using
First, open Bridge and go to
Batch Rename and then from the preset dropdown select
String Modification Then check the
Use Regular Expression checkbox. Now you can add RegEx to find and replace the pieces you want.
Here's a screenshot, I've included the RegEx I used to get rid of the numbers as well, you may need to change/refine it. (Check out the Current/New Filename at the bottom of my screenshot). I've also unchecked
Replace All you may or may not need that depending on how you want the RegEx to run.
I used Bridge CS5.1 for this, I assume it works similarly in higher versions of Bridge
I figure I'll also try to explain the RegEx (
\_[0-9]*) a bit since it's all magic.
\ escapses the
_ so regEx takes it literally. This eliminates the preceding underscore and also helps establish where RegEx should start replacing.
Next I wrote
[0-9] this will look for any characters that are
9 and any inbetween.
Lastly I added an
* so that the
[0-9] pattern would go indefinitely, until we hit a character that doesn't match the pattern (making sure we get all 4 digits)
Here's a helpful guide from the MDN