how to make changes on open figures?

I'm writing a code,that should make some changes on all of the open figures and then save them in png format with the same name. There are sometimes one, and sometimes more than figur open. Does anybody have an idea how I should do that?

Answer 1

[Walter Roberson]

fignums = findobj(0, 'type', 'figure');
for thisfig = fignums
  set(thisfig, 'Papersize', [8.5 11]);   %for example
end