v0.4.5

Added

• Saved backup destination — press n (from the disk list or inside the new backup menu) to set a default folder for backup images, such as a mapped network drive or UNC share. The path is validated before it is accepted: it must be absolute (Z:\backups or \\server\share\backups), the folder must exist, and the app writes and deletes a small probe file to prove the location is writable before trusting it with a multi-hour backup. Entering an empty path clears the saved destination.
• Persistent settings file — settings are now stored in %APPDATA%\diskutility\config.json (pretty-printed JSON, currently a single optional backup_dir key). The file and folder are created on first save; a corrupt or missing file falls back to defaults and is noted in the session log.
• Backup destination menu — pressing s now opens a "Backup — where should the image go?" picker instead of jumping straight to a path prompt. It lists your saved destination (if set), your home folder, and "Custom path…", showing the free space next to each folder. Navigate with Up/Down or j/k, choose with Enter, press n to set or change the saved destination, Esc to cancel.
• Image size and free-space check in the backup prompt — the backup path prompt and menu now show the size of the image that will be produced (the raw sector size of the selected disk). As you type a destination path, the prompt shows the free space there, colored green if the image fits and red with a "will not fit" warning if it does not.
• Mapped network drives resolved to UNC paths — when the saved destination starts with a mapped drive letter, the app looks up the drive's UNC target in HKCU\Network and stores/opens that form instead (for example Z:\backups becomes \\nas\share\backups). This is needed because mapped drives are usually invisible to an elevated (UAC) process; the resolution is recorded in the session log. If a drive-letter folder cannot be reached while running elevated, the error message suggests using the \\server\share form.

Changed

• Suggested backup filename now includes the date — the default image name is disk<N>-<name>-<YYYYMMDD>.img (previously disk<N>-<name>.img), built under whichever folder you picked in the backup menu. Choosing "Custom path…" starts with an empty prompt.
• Footer and help updated — the footer shows the new n backup dir shortcut, and the Help dialog (one line taller) documents n as "set a network drive / folder as the default backup destination".
• Input prompts grow to fit — the path prompt dialog expands from 7 to 9 rows when the image-size/free-space line is shown, and its text now wraps instead of being clipped.

Full Changelog: v0.4.4...v0.4.5