I suggest rephrasing the title to "How to dynamically generate file names", which is similar to this question.
Here's a short example demonstrating how you can do this:
suffixes = {'one', 'two', 'three', 'four', 'five'};
for j = 1:5
plot(rand(10,3));
saveas(gcf, ['image_', suffixes{j}, '.jpg']);
end
