iResizer for Mac OS X makes it a breeze to resize images

If you want to resize your JPEG images for the best web performance or create thumbnails for an image gallery check out iResizer for Mac OS X (10.7 or higher). It scales an image without changing important visual content such as people, buildings and animals — and avoids distortion of the important parts of the image.

iResizer is easy to use. Load the image you want to resize. Make a rough selection around the area you don't want to be affected when you resize the image. You can also, if you wish, make a selection around the content you want to discard (discard masks are ignored when enlarging an image). 

You can mark important elements in the image using the green marker. This technique is handy if you have areas of the image that you want to retain at the expense of other areas. You can use the red marker to select which features of the image should be discarded. Press the Smart Resize button. iResizer users "intelligently" generated textures pulled from the surrounding image data to scale the image. You can then save the result.

Normal resizing affects all pixels uniformly when you scale an image, iResizer resizing mostly affects pixels in areas that don't have important visual content. The utility lets you shrink or enlarge images to improve a composition, fit a layout, or change the orientation. It also can be used to remove a portion of an image in a consistent way. For example, you can turn a landscape picture into a square picture and close up the space between people in a image if they're too far apart.

With iResizer- -- which was recently revved to version 3.0 -- you can mark important elements in an image using a green marker that can be used to, for instance, protect people in the image. A red marker lets you choose which features of the image should be discarded. Version 3.0 offers some major algorithm improvements, stability improvements and interface enhancements. It also adds transparency support.

iResizer is easy to use. iResizer isn't for everyone. Is it for you? Yes, if you need to:

  • Match the aspect ratio of your photos and your prints;
  • Change the spacing between main objects;
  • Remove objects from photos;
  • Change image aspect ratio;
  • Fit entire photos on Instagram without cropping.

For such folks, it's an effective and reasonably priced tool — especially for a limited time. iResizer is normally $19.99, but it's on sale now for $9.99. A demo is available for download.