Novator slider customization

[Jorge Contreras]

Greetings,

Just today I'm starting on abantecart, so I'm as newbie as it gets.

I'm running v1.4.2 on a linux machine, in case it matters.

Right now I'm trying to edit the Home page carousel, and the documentation tells me to edit the HTML directly in the carousel block, but there's no specifics about image types or size requirements.  Or much of anything else actually.

By inspecting the page and searching my shop's files, I've figured out where to upload the new image files to, but I haven't been able to get the images to act right.  On my laptop they kind of work, but not on my phone.

Here's what it looks like on the laptop:  https://drumdr.com/drum-sales/

I've tried resizing in the HTML, but it seems to have no effect at all.

Suggestions?