Hey there,
You can do that by customizing the CSS, at the moment there is no other way. That’s a bit out of the scope of the support I can provide for a free plugin.
I’ll take note though – I think eventually I could make some sort of customizer (columns, layouts, etc.) for the plugin in a premium version, but at the moment I don’t know whether that will happen at all.
As a side note – I don’t recommend that you make titles visible only on mouseover. A lot of devices don’t have a mouse, which means that your website won’t look that good on them.
If you want a nice design for the portfolio – you can have a look at our WordPress themes at https://colormelon.com/themes
