Is there any way to use the System icons, located in:/System/Library/CoreServices/CoreTypes.bundle/Contents/Resources/ without having to add them to the Resource folder of my project in an application with AppleSript?
Yes, just use the POSIX path. If you are using display dialog, AppleScript in Xcode s a bit fussy, so you will need to explicitly coerce it:
display dialog "hello" with icon ("/System/Library/CoreServices/CoreTypes.bundle/Contents/Resources/GenericQuestionMarkIcon.icns" as POSIX file)
if you are using NSAlert, the icon property needs to be an image, so you can get one from the path, for example:
set myAlert to current application's NSAlert's alloc's init()
set myAlert's messageText to "hello"
set myAlert's icon to current application's NSImage's alloc's initByReferencingFile:"/System/Library/CoreServices/CoreTypes.bundle/Contents/Resources/GenericQuestionMarkIcon.icns"
myAlert's runModal()
For other objects that use an NSImage, you can get an image from the path in the same way, and set the object's image by using the relevant property or setter method:
set yourImageView's image to current application's NSImage's alloc's initByReferencingFile:"/System/Library/CoreServices/CoreTypes.bundle/Contents/Resources/GenericQuestionMarkIcon.icns"