Yes, you can add that for either all users (Use HKEY_CLASSES_ROOT keys) or for just your user use the HKEY_CURRENT_USER)
I'll just you the all users key HKEY_CLASSES_ROOT
- Open regedit and expand HKEY_CLASSES_ROOT
- Expand the * key
- Expand the shell key
- Right click on shell and select "New > Key"
- Name this whatever you want, it can be used as the text in the menu or I typically use it to order the menu entries so if I want a entry at the bottom for say opening a log file I would name the key "zzzzOpenLog"
- Click on the newly created key and edit the (Default) value and enter the text you want it to have so "Open Log" for my example
- With the zzzzOpenLog key selected you can add optional values like
- Position (type: string) and have Top or Bottom there may be others
- Icon (type: string) path to the .exe you want to use for the icon on the menu
- Now right click on zzzzOpenLog and select New > Key
- Name it command
- Select command and edit the (Default) value with the full path to the exe you want to launch plus the argument to pass it
- Example "C:\Windows\System32\mspaint.exe" "%1"
- This would open paint and %1 is always the file you are clicking on