Sorry i didn't get it before. Unfortunately Gallery content plugin doesn't support such a feature. However i made some changes in order to be compatible with your needs.Here are the steps:1. Download and uzip the gallery.plugin.zip file.2. Upload file gallery.plugin.php to folder: /components/com_content/plugins/gallery/
We want the plugins and modules to have as less configuration options as possible. Especially for the plugins the ideal format is this: {plugin}something{/plugin}, nothing else, no parameters, symbols, mathematical signs, quotes, etc.Most users get confused with many options, they need to install something and use it instantly. My main thinking is on newbies, not on advanced users. Elxis must be easy and fast to use for them. I also believe that sites should have a similar appearance from page to page, so a global option for the thumbnails width and height is enough. Finally, the included plugins are basic extensions, if you want more advacned or custom functionality you can create your own plugin with more options and different style.