Batch Resize Images Mac OSX in Preview App
Many people believe that you cannot batch resize multiple images in one click on a Mac, but this is not true. There are many things you can do with the built in native apps on Mac OS X which most people don't know about this is one of them. You don't need photoshop or any special app for resizing images, because Preview can do it perfectly well for you
its a 10 second job;
select all images in finder
right click and 'open with preview'
select 'edit/select all'
go to 'tools/adjust size'
change width or height of image/s
close app (autosaves)
job done