This tutorial explains how to programmatically add multiple images Magento 2. The additional images urls are reading from the CSV. I have downloaded the additional images from the remote directory.
This tutorial explains how to add image block shopify theme and make the blocks editable from the backend. Here it create a section in the backend where you upload the image and linked that to the collection.
This tutorial explains how to add content block homepage shopify. Here it explains how to create editable content blocks.
The extension adds contact form slider as shown below.This is a free sliding contact form magento extension.
This tutorial explain how to rewrite adminhtml form magento. The tutorial show how to extend magento extension admin form and add new form fields as shown below.