Need to resize a ton of images quickly. Check out the sips command.

sips -Z 1080 *.jpg

This sets the maximum height/width to a certain size in this case 1080. The -Z command sets the aspect ratio, which is great so we do not create a handful of lopsided or distorted images. Finally the .jpg denotes the image file to be resized – its worth noting that Terminal is case sensitive. This command can save you hours upon hours of hassle and headache, but just to make sure your ok with the output and always make sure to backup the originals in a separate location before running the command. We tend to go a bit overboard with this part and create two backups (one version zipped, that will be used for archieving purposes and the foldered version — stored outside of our working folders).

Learn more about the OSX Command Line at Treehouse: