The name of this application pretty much sums up what it does, which is providing a way to resize photos in batches. This might be useful if you want to upload some pictures to Facebook (etc): Albums look better when the pictures are all the same size.
Batch Picture Resizer also has a tool for adding watermarks to your pictures, either in text format or with a logo of your choice. Therefore if you're worried that your works of art might be stolen by unscrupulous web users/Facebook friends, you can protect your files.
Importing files to the interface is dead simple - just drag and drop them into it. The resize options are limited in this 30 day trial, and allow you to determine the height and width, resize maintaining the original ratios, or crop the images to size. It's not difficult to set your desired parameters, and pressing the START button does all the work for you. The watermark tool is also pretty easy to use. You can choose what the watermark is, how transparent it is, and where it will go, and the results look good.
Batch Picture Resizer is certainly a very efficient way of resizing your photos in large numbers, so it is recommendable if you find that necessary. Whether you'll want to pay for a registered copy after the trial is up is another matter.
There is nothing wrong with Batch Picture Resizer - it does exactly what you expect it to.