I'm looking for a way someone who's mastered dragging and dropping files into a FTP program can use, who occasionally uses directories to organise files (but still has over 5k images in one folder) can use to upload his hand-built website onto S3.

At present he's using FTP to one of my old servers, but I'm decommissioning it next month. Cheap shared hosting works out cheaper (due to the bandwidth this image-heavy site uses) but I'm curious if any startup's solved this use-case with Amazon S3?