If you want to rename your files in batch, it can be pain in the ass if you use the Windows explorer to rename the files. But there are some handy tools out there that can help you to rename your files in batches. Two of the file renaming utility that I use are ReNamer and Ant Renamer. Both tools are easy to use and have some advance features that make renaming the files much easier.
Ant Renamer 2
Some of the common features that both programs have are string replacement, insertion, deletion. So, if you want to replace certain string (ie: DSC with Photo), you can use these functions to do it.