Both Gnu Smalltalk and Smalltalk/X are able to use images, while GST is optimized for "normal source code" model, in ST/X it's mostly an artifact of implementat

Both Gnu Smalltalk and Smalltalk/X are able to use images, while GST is optimized for "normal source code" model, in ST/X it's mostly an artifact of implementation and file system resident source code is simply a way to store what essentially amounts to changes file in classical implementations (the killer feature is that you in most common case can use non-ST specific VCS without significant issues). In all I haven't seen ST implementation with good development tools that is not at least partially image based. The problem I see with ST IDEs is the fact that most advanced features work by introspecting live image state and autogenerating some source code, which completely break any attempts to meaningfully define what is (versionable) programmer-written input and what is derived tool output.