When converting a pseudocolor image to a grid, the IMAGEGRID command fails to create the specified colormap file. The GRIDPAINT command confirms this.
Arc:IMAGEGRID my_image my_grid my_grid
Arcplot: MAPE my_grid
Arcplot: GRIDPAINT my_grid # # # my_grid
ArcPlot: Colormap file my_grid not found, using default
If the specified output colormap file name is the same as the output grid, and no extension is provided for it, the colormap file will not be created.
Arc:IMAGEGRID my_image my_grid my_colormap
Arc:IMAGEGRID my_image my_grid my_grid.clr
The colormap file extension is arbitrary. You can assign any extension as long as you specify it when using the colormap.