How can I get the publication date property and the Image property from this page in sling model
You need to handle multiple use cases and conditions
1. the direct approach is getting from the current page. inside the sling model, read publication date, and the Image property from the currentPage reference object.
2. if the current page object does not contain these properties, then check for the parent page.
But, your requirement is you need to fetch these values into the other page. the other page must know this page path.
1. if it is the parent page, then you can use currentPage.getAbsoluteParent() directly point to that page and read those properties.
2. if it is not the parent page, then the page must be authored somewhere, either in component or page properties of the other page.
3. In your sling model, read that page path and pass it to the getResource("page path");