IMWRITE Write Matrix to Image File

Section: Input/Ouput Functions

Usage

Write the image data from the matrix into a given file. Note that FreeMat's support for imwrite is not complete. You can write images in the jpg,png,xpm,ppm and some other formats. The syntax for its use is 
  imwrite(A, filename)
  imwrite(A, map, filename)
  imwrite(A, map, filename, 'Alpha', alpha)

or Octave-style syntax:
  imwrite(filename, A)
  imwrite(filename, A, map)
  imwrite(filename, A, map, alpha)

where filename is the name of the file to write to. The input array A contains the image data (2D for gray or indexed, and 3D for color). If A is an integer array (int8, uint8, int16, uint16, int32, uint32), the values of its elements should be within 0-255. If A is a floating-point array (float or double), the value of its elements should be in the range [0,1]. map contains the colormap information (for indexed images), and alpha the alphamap (transparency).

Example

Here is a simple example of imread/imwrite. First, we generate a grayscale image and save it to an image file. 
--> a =  uint8(255*rand(64));
--> figure(1), image(a), colormap(gray)
--> title('image to save')
Warning: Newly defined variable nargin shadows a function of the same name.  Use clear nargin to recover access to the function
--> imwrite(a, 'test.bmp')

Then, we read image file and show it: 

--> b = imread('test.bmp');
--> figure(2), image(b), colormap(gray)
--> title('loaded image')
Warning: Newly defined variable nargin shadows a function of the same name.  Use clear nargin to recover access to the function