SunlitGreen Photo Editor, downloadable
here, is also bundled in the BatchBlitz suite.
It is a lightweight yet powerful photo enhancer and editor. It
enables you to view, resize, rotate, apply color corrections and
effects to your photos in an easy and professional way.
This Photo Editor tool has a separate license and can be used
independent of SunlitGreen BatchBlitz.
Just choose BatchBlitz menu option Tool > Photo Editor, or simply click button
on the main toolbar. The main window (with an opened
image) of Photo Editor may look like this:

The following sections briefly introduce some of the frequently
used operations.
Open an image, then choose menu option Image > Image Size.... In the "Image Size"
dialog, enter the new size values, and press OK. See below:

 |
Holding down the Alt key changes the Cancel
button in the above dialog into a Reset button. This holds
true for most dialogs in Photo Editor. |
Open an image, then choose menu option Image > Canvas Size.... In the "Canvas
Size" dialog, enter the new canvas size values, and press OK. Note
you can specify an anchor position, as shown in the below
image.

Open an image, then choose menu option Adjust > Color Balance.... In the "Color
Balance" dialog, drag appropriate sliders for a desired image
tone.
As shown in the below image, we drag the "Cyan-Red" slider
towards left for the midtones in current image.

This effectively reduces the redness from the image, as can be
seen in the below example:

You can correct exposure or contrast of your images with a
simple click. Just choose menu option Adjust > Auto Levels or Adjust > Auto Contrast.
In the below example, Auto
Contrast has been used to correct the overall contrast.

The Levels dialog lets you
adjust intensity levels of the shadows, midtones (or gamma) and
highlights in an image. Just choose menu option Adjust > Levels....
In this dialog, you take advantage of the histogram to get some
feedback on your image and make adjustments accordingly.
Note that adjustment can be made to individual color channels as
well as the composite channel (RGB channel). The Channel dropdown list specifies the targeted
channel.

The Curves dialog lets you
increase the contrast, or selectively enhance the details. Just
choose menu option Adjust >
Curves....
In the curve graph, each small square on the curve defines a
control point. The black square indicates the current (or selected)
point. You can add up to 8 different control points (not including
the two default endpoints) to a curve.
To add a new control point, just click on the curve. To delete one,
hold down the Ctrl key and click it. To select a point, simply
click it. To move a point, select it and drag around.

The Photo Editor online documentation provides more detailed
information.