Can OS X's Grab utility be made to save images in formats other than .tiff? I'm specifically looking to extend / adjust Grab for the sake of a quick, short workflow, rather than looking for another tool to use.
What kind of file are you wanting?
If you use the built-in screenshot shortcuts (⌘-Shift-3 / 4) it will save the screenshots by default as .png files. You can find more about this by checking out the SuperUser question: How to take screenshots in Mac OS X?
You can also adjust the file type saved by the screenshot shortcuts (and
Grab (the OSX screen capture utility) creates TIFFs by default, and there is no way to change that (The settings dialog does not offer a file format option, and I didn't find any other way). It does so irrespective of the default screen capture format (which is PNG unless you have a very old OS X version).
That is, even if you use the
Converting the image using Preview or other tools (even Automator actions) is not practical, it's much too cumbersome and takes too long.
The solution: don't use Grab.
I recommend to use the keyboard shortcuts as suggested above, which is by far the fastest way, once you know them by heart.
The alternatives would be to use dedicated and more powerful screen capture utilities such as Skitch, which also include annotation tools so you can highlight and label certain parts of the screenshot.
No, but you can use Preview to convert the image. If you're doing this as part of a workflow, you could use Automator to do the conversation automatically.
If you want a screenshot in PNG format, you can use ⌘+Shift+3 to take the screenshot.
The Automator utility has a task called "Change Type of Images" that takes in a set of images and converts them into another file format. You could create a Workflow or even a Folder Action (possibly attached to the Desktop folder) that would allow you to drop the images onto the workflow and convert them automatically.