How to display different images in sidebar for different pages

I am new to wordpress and I have a theme that I created from scratch and I need to know how to show different images in the sidebar for different pages. These images will go under the category business partners and right know it shows the same pics on every page. I have a query that is taking the first 8 post in this category and displaying them but I want to display different pics on different pages. the website is https://www.mywlas.com