As you have probably guessed from the program name, Batch Picture Resizer allows you to change the size of multiple image files at once. However, it may offer you other options as well, such as converting images format, rotating and flipping, renaming and adding both text and image watermarks to them. All the features support batch processing of your image files.
Batch Picture Resizer comes with an uncluttered and intuitive user interface where you can add all the images you want to edit, either by single files or by folders. Then you can select what functions or effects you want to apply to them through a tabbed system. Resize tab, which of course is designed for the main function of the program, allows you to provide both the new width and height of your images in pixels or percentage, though you can also select any of the predefined standard sizes or percentages this section puts at your disposal. Convert tab, on the other hand, allows you to select one of the 7 available output formats (JPEG, BMP, GIF, PNG, PCX, TIFF or TGA) or simply opt for keeping the original files' format. If you select an output format, however, you need to provide the new DPI and JPEG quality values, even if you select a format other than JPEG. Unfortunately, this is a setback for Batch Picture Resizer, as it doesn't allow you to configure the specific parameters of each supported output format.
As for the Rotate tab, it allows you to select the rotation angle and sense, or the flipping sense (horizontal or vertical) for your images. Next is the Effects tab and there you can just turn your images into grayscale ones or normalize their colors using the program's internal algorithm, with no configurable parameters. Finally, under the Tools tab you can rename your image files by adding prefixes or suffixes to their file names, and add text/image watermarks to your images by specifying their transparency level and exact position.
To sum it all up, Batch Picture Resizer allows you to do much more than its name implies. However, the program lacks some parameters and options that may require configuration, specially for advanced users. Anyway, if you need to apply simple editing functions to multiple image files at once without much complication, I would still say Batch Picture Resizer is a good option to try.