| Value | Description | 
|---|---|
| iecsIO (0) | The content of the image has changed due to loading or other TImageEnIO method | 
| iecsProc (1) | The content of the image has changed due to image editing using TImageEnProc | 
| iecsBitmap (2) | The content of the image has changed for other reasons (e.g. assignment or layer merging) | 
| iecsLayer (3) | Properties of a layer have been changed, e.g. by adding, removing, resizing, moving or setting layer properties | 
| iecsUndo (4) | The content of the image has changed due to Undo or Redo |