saving figure with minimal white space without ballooning the size

I saved a file with

set(gca, 'LooseInset', get(gca, 'TightInset'));
set(gcf, 'PaperPositionMode', 'auto');
saveas(gcf, filename, 'epsc');

but it had too much white space. It was 1.2mb in size.

So I saved it with

exportgraphics(gcf, filename, 'ContentType', 'vector', 'Padding', 0);

This resolved the white space issue, but it was 79mb in size.

Is there a way to save the figure without the huge jump in file size? I am trying to save a complex phase portrait. I want to save several of them, so I don't want to have to do the cropping in an external program. Thanks.

[xingxingcui]

Your complex phase portrait is graphic or image type?

[Barbara Margolius]

I'm sure you have identified the problem. I adapted some code from file exchange to generate my image and presumably it is raster rather than vector. Thanks.