Hello eparts4yourcar -
We are not aware of any issues with the Plain White template and images and when I test this template with a newly posted listing I am unable to reproduce an issue with the images scrolling (the scroll is a bit different on a mobile device, tapping the arrows transitions the images) when I view them in the full item description of the eBay app. In a quick review of your active listings, I was unable to locate one that was using a template other than one of your custom templates, so if you are running into this issue with a particular listing that uses the Plain White template, please file a support case from under the Help tab of the site letting us know what you are encountering and a sample listing or two that displays this so we can have a further look into it.
I did check some of the most recently posted items using the custom template and found that the scrolling was operating as expected in the item description area - the main images changed accordingly when I tapped on the smaller images from the description area, so it is unclear what may be occurring for you or if there is a chance it is device specific. If you are reviewing the listings on the full item description page and are not able to have the images change accordingly, please do file a support case and let us know which listings are affected and which device you are using when you run into this so we can take a look.