The batch file rename feature is definitely welcomed
A batch renaming option has been added to the Finder in Yosemite: if you need to rename multiple files at once, select them, then choose “Rename [x] Items…” from the contextual menu. This will open a modal dialog with three options to batch rename files: Replace Text, Add Text, and Format. The first two are rather self-explanatory: one replaces a string of text found in the filename and the other can append or prepend text to the filename. Format is more advanced, as it lets you pick a format name with index, date, or counter to be placed before or after the filename with an option for a custom format as well.
Dope feature, especially for all my blogger folks who use pictures in their posts. If you didn’t know, for SEO juice, you should rename all your pictures to include the title of your post and/or keywords