convert signals to spectrogram

Hi, I want to convert the existing signals to spectrogram images automatically and save them in jpg format, so how do I change the following code to execute the code correctly?

Thank you!

clc

clear all

close all

Path = 'IS\*.mat';

Files = dir(Path);

for i=1:length(Files)

fn = [Path(1:end-5) Files(i,1).name];

load(fn);

y = val(1:3600);

[thr,sorh,keepapp] = ddencmp('den','wv',y);

sig1 =wdencmp('gbl',y,'sym10',10,thr,sorh,keepapp);

fs=128;

pspectrum(sig1,fs,'spectrogram','TimeResolution',0.5)

title('pspectrum Signal')

temp=[num2str(i,'%04d')];

saveas(temp,'jpg');

end