You can indeed solve this problem a wide variety of ways, including some slick Mac graphical utilities that you can find at VersionTracker.com, but let's look at a simple script that solves this problem because I like writing shell scripts!

The basic idea is that we're going to replace "IMG_" with a pattern that you specify. For example, perhaps you need "prod-v11" so that IMG_0001.PNG becomes "prod-v11-0001.PNG". Better yet, let's go ahead and fix the all uppercase filename suffix while we're at it too, so it'll end up as "prod-v11-0001.png".

To do this, we'll need to transform the old file name into a new one. This is easily done with the powerful "sed" command.

Here's how I'd do it:

Well, what I'm doing here is actually transforming IMG_0001.PNG into "pattern01.png" because I know that for my uses I'll never have more than 99 images in the same collection. If you might have more, you'll want to use IMG_0 instead of IMG_00.

The transforms are to substitute IMG_00 for the basename pattern, then PNG substituted with png. See how that works?

Since I don't want to type in each filename but have them all transform magically in a loop, that's exactly how I'll code it:

One more piece is necessary for this to be a useful script: the ability to specify the pattern that should be used for the rename. This is done by grabbing the command argument to the script.

Here's my full script:

When run against a bunch of iPhone screen shots on my Mac, here's what I see:

Quickly and easily done. Works for you, I hope?