Turning a sequence of images into a gif directly

The process whereby one converts a figure to an image to a GIF is well-documented, but what if I instead have a sequence of images (actually, just a sequence of square arrays I would like to graphically represent in some way) and I want to turn them into a gif?

This is the process which I guessed would give me some success, and indeed the program doesn't spit out any errors. It also, as far as I'm aware, doesn't spit out any output (I've searched my computer for testAnimated.gif and it appears to not exist).

filename = 'testAnimated.gif';

for idx = 1:length(t)
    Smap= [AN ARRAY OBTAINED IN SOME WAY]
    A=image(Smap*20);
    map=colormap(gray);
    %[A,map] = rgb2ind(image(X); colormap(map));
    if idx == 1
        imwrite(A,map,filename,'gif','LoopCount',Inf,'DelayTime',1);
    else
        imwrite(A,map,filename,'gif','WriteMode','append','DelayTime',1);
    end
end

Any help would be appreciated.

[Aquatris]

You are missing some code. Take a look at the answer to this question and modify your code accordingly.

[KSSV]

YOur A is of class matlab.graphics.primitive.Image. YOu cannot write this using imwrite.