Hello,
environment: Joomla 3.8.6., agency template quickstart package installed

I would like to resize the images on the home page. So I enabled „Resize Images“ in the module „mod_roksprocket“.

Didn't work, even when I insert a new item to the slideshow.

Regards

Hi there,
if you want to use this function you have to clean your Browser and Joomla cache before.
BTW its not recommend to use the reszize image function, because of the responsibilty issue.

Hi,
how to avoid that image is scaled up to e.g. 1615x8019 on desktop?

Which roksprocket design exactly?
The slideshow ( features) is already scaling the images to 100% of the outer DIV.
And thats what I have said, please dont use a fix width or you will loose the mobile view.