Mass Image Compressor is exactly what its name implies: a program for reducing the file size of your pictures. This application might prove to be of good use if you wish to attach a large-sized photo to an email and wish to avoid going over the size limit imposed by the email sharing service.
The utility brings you a simple interface that consists of a single window. There, you will be able to import the folder containing the photos you wish to compress, configure the output settings according to your needs, and preview the output files before launching the data compression process. You don't need much computer experience in order to work with this tool, even if you're new with this type of Windows applications.
In my testing, I imported a directory that contained various types of image formats (JPEG, BMP, GIF, TIFF, etc.). The program immediately compressed the pictures, without losing their quality in the process. It also preserved the image metadata.
An advantage is that you can convert the compressed files if needed. Unfortunately, the application supports only 2 output formats: JPEG and PNG. Still, this isn't a big deal as the aforementioned image formats are very popular and supported by a wide range of Windows tools.
All in all, I'd say it's worth installing this free program on your PC if you're looking for an efficient way to compress your images.