Property and Real Estate Management Plugin for WordPress.
The plugin uses your theme’s stylesheet, but also has its own. Inside the plugin folder (wp-content/plugins/wp-imovel/templates) there is a file called "wp_imovel.css". Copy that file to your template directory, and the plugin will automatically switch to using the settings in that file, and will not load the default one anymore. That way when you upgrade the plugin, your custom CSS will not be overwritten. Same goes for all the other template files.
The easy way is to go to the Settings -> Properties page, many settings can be configured there.
You would do it the same way as if you were editing a post or a page. On the property editing page, click the Image icon above the content area, and upload images into the media library. If you want the images to show up on the front-end, you may want to visit Appearance -> Widgets and setup the Property Gallery widget to show up on the property page.