   Game editor design decision - create project files at beginning or when saved?
  I'm creating an editor for my game and have a design decision. The editor will be a lot like RPGMaker XP and have options to import image resources, like tilesets. Each game project will have a file hierarchy like this.Editor.exe-[Projects]  -[Project1]    -gamefile.game    -[Tilesets] -tileset1.png  -[Project2]    -gamefile.game    -[Tilesets] -tileset1.pngThe decision I'm trying to make is whether I should:1) Save tileset1.png to the hard drive when imported.2) Keep tileset1.png in memory and only save to hard drive when project is saved.This applies to all game project data including the file/folder structure.RPGMaker XP creates the file/folder structure when a new project is first created, and copies the imported file to the game folder when imported.At first I was planning on doing this, but I noticed programs such as Visual Studio don't create any files on the hard drive when you create a project and add files such as images. It only saves the files once the user saves the project.The second method is more appealing and the only downside I could think of is it would use more memory.I'm wondering what you guys think is the best method and any unforseen problems or benefits.   