Somewhere probably in my long-ago editing, the image directions got transposed. Here's the patch:
===begin===
diff --git a/industry/grocers.dat b/industry/grocers.dat
index 31841e8..5691ab2 100644
--- a/industry/grocers.dat
+++ b/industry/grocers.dat
@@ -57,10 +57,10 @@ InputCapacity[0]=14
InputFactor[0]=100
#InputSupplier[0]=2
Dims=1,1,4
-BackImage[2][0][0][0][0][0]=grocers.0.2
-BackImage[1][0][0][0][0][0]=grocers.0.3
-BackImage[0][0][0][0][0][0]=grocers.0.0
-BackImage[3][0][0][0][0][0]=grocers.0.1
+BackImage[2][0][0][0][0][0]=grocers.0.0
+BackImage[1][0][0][0][0][0]=grocers.0.1
+BackImage[0][0][0][0][0][0]=grocers.0.2
+BackImage[3][0][0][0][0][0]=grocers.0.3
upgrade[0]=Grocer1900
upgrade[1]=Grocer1945
--------------------
===end===
p.s., I sure do wish we could draw one shop or factory with player-foreground and player-background color scales, and have the MapColor (and a corresponding MapColor2) fill the various awnings or sign-boards for the particular goods types. Maybe one day...
Splendid, thank you for the fix - now implemented.
The factory colour drawing thing is in principle a nice idea, although I am not likely to have time to deal with that sort of thing for a long time. Also, I do not know whether this specific suggestion is feasible or not in the current graphics engine. However, anyone who would like to have a go at this is welcome to try.