change map image formats to workaround stb_image bug

stb_connected_components.h

@@ -33,7 +33,7 @@
 //    - better API documentation
 //    - more comments
 //    - try re-integrating naive algorithm & compare performance
-//    - more optimized batching (current approach still recomputes clumps many times)
+//    - more optimized batching (current approach still recomputes local clumps many times)
 //    - function for setting a grid of squares at once (just use batching)
 //    - shrink data by storing only, say, 2X max exits
 //      (instead of max exits per clump), and repack cluster

tests/stb.dsp

@@ -42,7 +42,7 @@ RSC=rc.exe
 # PROP Ignore_Export_Lib 0
 # PROP Target_Dir ""
 # ADD BASE CPP /nologo /W3 /GX /O2 /D "WIN32" /D "NDEBUG" /D "_CONSOLE" /D "_MBCS" /YX /FD /c
-# ADD CPP /nologo /G6 /MT /W3 /GX /Z7 /O2 /Ob2 /I ".." /D "WIN32" /D "NDEBUG" /D "_CONSOLE" /D "_MBCS" /D "TT_TEST" /FD /c
+# ADD CPP /nologo /G6 /MT /W3 /GX /Z7 /O2 /Ob2 /I ".." /D "WIN32" /D "NDEBUG" /D "_CONSOLE" /D "_MBCS" /D "GRID_TEST" /FD /c
 # ADD BASE RSC /l 0x409 /d "NDEBUG"
 # ADD RSC /l 0x409 /d "NDEBUG"
 BSC32=bscmake.exe