Many PC users in many lines of work will suddenly need to change the size or format of a whole bunch of images at the same time. It's really tedious to resize each image one by one, and it can take you all day--or longer. An app that can speed this process would be welcome indeed. SimpleSizer ($8, 14-day free trial) doesn't quite get there.
A good resizer program should allow you to select "keep aspect ratio" and then choose either a height or a width; the app would then resize to that selected single dimension, preserving the aspect ratio for the other dimension. In other words, resizing a folder full of large image scans to 1,000 pixels wide will give you a different height for each.
Unfortunately, there's no way for SimpleSizer to do that. In fact, when Keep Original Aspect Ratio is checked, the app defaults to resizing for height every time, ignoring width, and there's no way to change that.
SimpleSizer also can't change the DPI (dots per inch) of an image file during the resizing process, so you're stuck with whatever DPI you scanned the image in at. DPI control is important for those who deal in book printing, publishing, t-shirt making, web design, and many other occupations that need to modify a lot of image files to exact specifications. A glaring omission.
Adobe Photoshop has the ability to set up a macro to do anything you want to a single image, and then duplicate that process over an entire folder of images. I would expect that a standalone image resizing app should at least be able to complete with that functionality.
Note: The trial lasts 14 days and has a nag screen at the beginning. The full version costs 5 Euros; the price given in dollars reflects the exchange rate on the day this review was posted.