Resize files of any size preserving the source format.
You will need this option if the source image contains extra non-graphics information (EXIF, IPTC etc.).
Changing file format.
Very often the huge image is saved into the file of an inappropriate format - for example, uncompressed BMP format. It will make sense to convert the image into some other format with a more powerful compression. This will surely reduce the size of your file on hard disk drive. It is difficult to overestimate the convenience of this change.
Recompressing huge files to reduce their size.
Even if the file is saved into the correct format, it will often make sense to save it into the same format with better compression. For example, using correct compression for faxes will make their file size 100 times smaller.
Preparing images for publishing, illustrating, uploading to websites and sending via email.
It is the classical and most popular application of ImageConverter Plus. The program will resize your huge files until their size is ideal for publishing.