Almost any decent photo enhancement app for the Mac does the basics. Crop, slice, resize, and save in a variety of file formats. Few of them do it as easy as MagicCrop, an inexpensive multi-trick pony app for the Mac that could probably use a different name because crop is only one of the tricks.
So, that’s a good place to start the description. MagicCrop crops but in a way that’s actually useful and easy. Drag and crop, or define the aspect ratio, then drag and crop. Take a single photo with multiple subjects, and crop as needed for multiple photos.
Unusual for inexpensive graphic apps is MagicCrop’s ability to slice and dice images for the web. Set the number of row and column divisions and MagicCrop does the cutting automatically.
Each slice or cropped photo can be resized, too. And, files can be saved as JPG, TIFF, PNG, BMP, or PSDs. The slice feature also generates HTML for each slice. Parameters for crop, slice, and resize can be saved as a preset for future use.
And, importantly, crop, slice, resize options can be combined and automatically executed in one step. Considering how often all those functions are used I’m surprised MagicCrop carries such a low price.