similar to the Windows XP Powertoy tool for re-sizing images this tool demonstrates how to write a context menu handler and use other shell services for re-sizing and re-encoding image file types. this is accessed via the context menu for items in a "Resize Pictures" cascade...

this sample demonstrates

1) how to register a per user context menu handler

2) how to implement IContextMenu and invoking the verbs on a background thread (to avoid hanging the UI of the caller)

3) the use of IShellItemArray and IShellItem that can be produced from the data object passed to the extension

4) use of the shell image manipulation helper object CLSID_ShellImageDataFactory/IShellImageDataFactory

5) the use of the shell progress dialog CLSID_ProgressDialog/IProgressDialog for displaying progress

Chris