To exclude URLs just go to:
Configuration > Exclude (in the very top menu bar)
To exclude URLs within a specific folder, use the following regex:
The above regex, will stop Screaming Frog from Crawling the customer/account folder and the cart folder.
Excluding Images –
Ive just been using the image extensions to block them in the crawl, e.g.
Although you can block them in the Configuration>Spider menu too.