[R] Legend in image.plot( )

[Sumukh Sathnur]

Hello all,

Using image.plot from the fields package, I created a heatmap for a 
matrix I had saved as a text file. Everything works fine, but my legend 
goes up to a value of 300 (the maximum value in my matrix) whereas my 
scale goes up to 20 for assigning colors. Is there any way to truncate 
the legend at the highest value to which my intervals go? In other 
words, is there a way to make the legend stop at 20 on every matrix I 
use this for rather than the highest value in the matrix?

Thanks in advance,
Sumukh