V1541Commander allows you to create and modify D64 disk images (for the Commodore 1541 floppy drive).

• v1.1 Changes
  * Allow to disable automatic image rewrite when opening an image with broken filesystem
  * Images with broken filesystems are read-only
  * Allow saving an image with broken filesystem
  * Warn before overflowing disk capacity or directory
  * Add a "settings" dialog
  * Full drag&drop support (files and text)
  * fix: set correct window icon on win32
  * several UI improvements: calculate sizes more reliably. Especially the directory list should now look ok on any screen resolution (DPI).

Check out - https://github.com/excess-c64/v1541commander for more info.