In order to add an image to a block in Drupal, you can use the Image Block module.
Step 1: To activate this module, login to your administrative dashboard and go to Modules
Step 2: Scroll down the page and enable the Image Block module.
Step 3: After that navigate to Structure -> Blocks
Step 4: You will see a new link “Add image block” . You can use this new functionality to configure an image block for your Drupal system.
Step 5: After you have completed with the configuration of your new image block, click on the Save block button.