I work using the OceanWP theme in WordPress.com. I have created a slide show using the Background Type option. Image sizes can be adjusted for laptop and tablets, but not for mobile devices (images too big).

How to resize images automatically to fit mobile screens? Two plugins installed and activated (‘Adaptive Images for WordPress’ and ‘RICG Responsive Images’) but they have had no effect on the mobile images. Am I doing something wrong? One video said I should place the appropriate html code in the Appearance Editor, but my Appearance function does not have an Editor listed. Any advice you can offer. Is there a plugin for this? I am new to HTML and WordPress. Thank you for any help on this!