photo Drop is a polished gem of an application that does one thing quickly, stylishly and without any fuss. It allows you to create droplets onto which you can drag and drop image files in order to perform a number of different modifications. It acts as a front end for the command line tool
man sips at the terminal if you want to find out more), and allows you to flip, resize, crop or rotate images, change the image format or even add copyright information. You just fill in the appropriate values in the form, hit Save Droplet, and you've got something you can park on the Desktop and drop a selection of files on to. It's a great way of quickly resizing images for the web to a standard maximum dimension (i.e. no dimension larger than 600px).
Yes, I know that you can do this in Automator, and of course you can do it directly in
sips, but there's something very pleasing and streamlined about this tool, like a favourite, well-sharpened pen knife.