NoPaint is a small utility that can be described as a 'sprite file organiser'.

Version 1.05, 2003-01-31 (download). 

Basically Nopaint displays sprite files you drag to it in filer like windows and unlike Paint lets you to move your sprites within the file allowing you to classify for example filetype icons. It's main features are:

• Full drag and drop allowing you to move/copy sprites within the file or export them to other files/applications.
• Support of the global clipboard protocol (Cut/Copy/Paste between different applications).
• Individuals sprites can be renamed by ALT-clicking on their names.
• Keyboard shorcuts are implemented for most of the operations.