How to convert a .PNG file to a different size

I have existing .PNG file as an output from following:

 %Plot I:
X=datenum(tvec_SDstart);
Y=Carr_Fvec/1e6;
Z=magSpectrumMat_dB;
Tstart_num=datenum(Tstart);
Tend_num=datenum(Tend);
%
[X, Y]=meshgrid(X,Y);
h=surf(X,Y,Z);
set(h,'EdgeColor','none')
%
grid off
axis tight
view([90 90]);                                                              %Set view angle as Top-Flat 2D plot
colormap(jet);
%
% Create title and label
ax=gca;
set(ax,'FontAngle','italic','FontSize',8,'XColor',[0.0784313753247261 0.168627455830574 0.549019634723663],'YColor',[0.0784313753247261 0.168627455830574 0.549019634723663]);
set(ax,'XDir','reverse','XTick',linspace(X(1),X(end),6),'XLim',[Tstart_num Tend_num]);   % Set the plot with XLim between the user defined Tstart/Tend Time
datetick('x','HH:MM:SS.FFF','keepticks','keeplimits');
%
plotname_PSD = sprintf('PSD vs Time Collected on %s', datestr(Date));
title(plotname_PSD,'FontSize',16,'Color',[0.0784313753247261 0.168627455830574 0.549019634723663]);
xlabel('Time');
ylabel('Frequency (MHz)');
zlabel('Magnitude (dB)');
%
% Create colorbar
set(ax,'CLim',Plotscale);
colorbar;
%
% Print to PNG file
print(plotname_PSD, '-dpng');
%

Beside the file, I would like to convert to another long narrow PNG figure (w: 3 inches, L: 5.2 inches)

What is the best way to do this?

Answer 1

[Image Analyst]

I think export_fig() lets you specify the saved image's rows and columns to get the size you want. https://www.mathworks.com/matlabcentral/fileexchange/23629-export-fig