XnConvert

XnConvert is a free image editing and converting utility created for Mac. You can use this efficient application if you need to prepare a collection of pictures for an album.

It helps you resize, watermark, and rotate your favorite photos, as well as apply various visual effects to them.

The main window of the program is divided into 6 panels. In the first screen you can import the photos you wish to alter or convert. The application allows you to import as many images as you need as it provides you with support for batch processing. You can also load folders which contain pictures.

The next thing you need to do is to select the type of tasks you wish XnConvert to complete. All assignments are nicely organized into a list which can always be altered if necessary. Each editing tool comes with its own set of output settings which can easily be configured even by average computer users.

The Output window displays various output settings as well. You can choose the preferred output format from a long list of image profiles. Furthermore, the program is capable of preserving the metadata of the original pictures and can batch rename the input files if needed.

In my testing, the utility worked perfectly. I easily configured the output settings according to my needs and the program immediately generated the new images. What's more, it used minimum CPU resources while exporting the pictures.

Personally, I think XnConvert is one of the best image altering and converting tools designed for Mac. This program is packed with dozens of useful features, offers you quality output files, and is free. So, I can't find any reasons why you shouldn't give it a try on your computer.