How to adjust the size then upload multiple images:
This comes with a "workflow" that allows you select images in Finder, resize them, then upload them. It was a bit tricky figuring out how to set the paths correctly at first, but once I got that right it works beautifully!
Open the workflow in Automator, adjust the paths and any other settings including your FTP settings, then Save As Plugin... for Finder. Now, select your images in Finder, right-click, and under Automator select your workflow.