PhotoBulk is an OS X app that should interest webmasters, photographers and anyone who must manage and edit a lot of images.
PhotoBult can watermark images, bulk resize them and optimize photos by reducing file size. It's all very fast, and the app supports a variety of formats including JPEG, PNG, GIF, BMP and TIFF. Photoshop's native format is not supported, and the optimization routines only support JPEG and PNG.
I put the app to work on some of my landscape photos, and found it speedy and reliable. First I tried the watermark function. I could set the font type and size, and drag it anywhere on the image. I could also set the transparency (by the way, if you are setting a copyright symbol it's Option-G on a Mac).
The bulk resize function also worked well. Take your image, and input a new number of pixels for width and height. Optimization also worked well. I chose the default setting, and found that my JPEGs were reduced about 75 percent in file size with no obvious change in quality. When I magnified the image to 300 percent I could see a slight increase in noise in the shadows.
You can create presets, and then do hundreds or even thousands of photos at once, sending them to a folder of your choice. Of course, your originals remain untouched.
You can download a trial version of the software here if you want to see how it works before buying.
I should also note there are other alternatives to PhotoBulk, both free and paid. Photoshop has some tools (scripts menu under File menu) that will allow some automated changes to file types and size. Phatch is a free batch editor that has 35 functions including resize, rotate and add shadows.
I could find a lot of uses for PhotoBulk when preparing images for my website, or to share with others. The app is simple to use, and needs to run on OS X 10.7 or higher and a 64-bit processor.