MATLAB: Saving grayscale image as it appears in jet colormap of imagesc

colorcolormapgrayscaleimagescjetsavesaving

Hello, I have a grayscale TIF images (although it says it is TrueColor, nevermind). I need to convert them to grayscale and save it as it appears in imagesc(), colormap(jet) i.e. color picture.
Matlab code I use:
N = 4
FNAMEFMT = 'Frame%d.tif';
% Load images
for i=1:N
  IMAGES = imread(sprintf(FNAMEFMT, i));
  IMAGES = rgb2gray(IMAGES); 
  fname = sprintf('%s\\Frame%d.tif','C:\Project',i);
  imagesc(IMAGES); axis image; colorbar; colormap(jet);
  imwrite(IMAGES, fname, 'tif');
end
The pictures I import to MATLAB looking like that: http://img845.imageshack.us/img845/531/frame1m.png
And I need to save them looking like that: http://img850.imageshack.us/img850/5444/printscreenl.jpg
But the code I provided saves them again as black/white/gray.
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