Is it possibile to make controls in a form depending on each other? For example if Control1 has options "1, 2, 3" and Control2 has options "x, y, z". Then I select option 1 in Control1, now only options y & z should be selectable in Control2 and vice versa. Is this possibile? And then on top of that, is it possibile to make images on a form dynamic like that. So let's say, there is a different image displayed if I select 1 and z than when I select 3 and y?
Nintex Forms: Dynamic Options
What you're talking about with the options sounds like a Cascading Drop Down. There are some stellar posts about that, feel free to search on your own, but here are a few:
Dropdown cascading lookup with 2 filters fields !!
Three-Tier Cascading Drop Downs: Do Go Chasing Waterfalls!
Cascading drop downs and Nintex Forms for SharePoint
As for your image one, that could be possible. Here are a few examples:
Set image based on location in Forms - this one is setting an image based on geolocation
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