draw image of a matrix
eimage(matrix[,colorMap])
matrix :
rows x cols matrix for image
if colorMap=-1 then
image is filled with RGB values
(value=R*2^16+G*2^8+B and R,G,B are integer of 0:255)
else
matrix is filled with indices of colormap
or a string of filename of a JPEG-file
colorMap :
define own colormap
default:colorMap=ecolors(eImageDefaultColorMap)