I'm working with ren'py and I'm having issues with the Batch Export features, in ren'py (as far as i know) you need to have the syntax as follows for PNG files in the character name "[character name] [Position/Expression/Etc.].png" and I'm not sure how to export as "New_Character_1 Default_Clothing_Style-Default_Hairstyle-Default_Expression.png" instead of "New_Character_1-Default_Clothing_Style-Default_Hairstyle-Default_Expression.png", it might just be a 1 character difference, but I'm going to be working with hundreds of expressions, so it would be tedious and time consuming. is it possible to change the export syntax?

Sorry, right now it's still not possible within the app, but for temporary measure you can use tools such as ReNamer (https://www.den4b.com/products/renamer) to achieve similar results. We'll put this feature into the list for next update!

Super late addition, but just in case others are having this problem :
It's possible in Windows to use PowerShell to batch rename files.  In this example, you'd want something like...

Get-ChildItem | Foreach-Object{     Rename-Item -Path $_.FullName -NewName $_.Name.Replace(" Default","-Default") }

or possibly just

Get-ChildItem | Foreach-Object{     Rename-Item -Path $_.FullName -NewName $_.Name.Replace(" ","-") }  

There are a couple of ways to do it - google/duckduckgo for Powershell batch rename' and look at the stackoverflow website entries, that's where most of the good stuff is at.