function image = optostim_image(filename, cmap)
if nargin < 1
    disp('usage:   optostim_image(filename, colormap(opt)');
    disp('example: optostim_image(''21-Mar-2005_001_image.mat'', ''gray'')');
else
    image = load(filename);
    if nargin == 2
        imagesc(image.x_scale, image.y_scale, image.image_data)
        eval(['colormap ' cmap])
    end
end