Today I saw someone ask about installing Img on macosx.  I couldn't recommend teapot-client because it fails:

 - teapot.rkeene.org contains Img 1.4
 - teapot.activestate.com contains Img 1.4.2

thus Activestate wins:

$ tclsh teapot-client.tcl get vfs x86_64 macosx Img
Fetched Extensions:
  Img v1.4.2
$ find vfs/
vfs/
vfs/lib
vfs/lib/Img1.4.2
vfs/lib/Img1.4.2/Img.tcl
vfs/lib/Img1.4.2/pkgIndex.tcl

notice that the dependencies aren't picked up, because teapot-client expects zip packages to include teapot.txt.  Instead:

$ grep -R Meta\ require vfs/
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {Tcl 8.4}
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {Tk 8.4}
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {img::bmp 1.4.2-2}
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {img::gif 1.4.2-2}
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {img::ico 1.4.2-2}
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {img::jpeg 1.4.2-2}
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {img::pcx 1.4.2-2}
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {img::pixmap 1.4.2-2}
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {img::png 1.4.2-2}
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {img::ppm 1.4.2-2}
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {img::ps 1.4.2-2}
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {img::sgi 1.4.2-2}
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {img::sun 1.4.2-2}
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {img::tga 1.4.2-2}
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {img::tiff 1.4.2-2}
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {img::window 1.4.2-2}
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {img::xbm 1.4.2-2}
vfs/lib/Img1.4.2/Img.tcl:# Meta require         {img::xpm 1.4.2-2}

I suppose teapot-client should, if a zip doesn't contain teapot.txt, look inside all its *.tcl files for embedded teapot data.