Eh, it's really not that different in MVC. You work with controllers (which tend to be separated by task, so you'd have a Slideshow controller, or something like that, here) and their methods, each representing a particular task. So, your button that uploads and crops and positions? Handled by a POST method in the controller (and, yeah, you can do it asynchronously easily). Same with the record slideshow functionality (a GET method to display it, a POST method to save the recording).
If I weren't so rusty, yes, I could do it in a day. No, I'm not bragging or lying. Web forms is fast for you because you're used to it, not because the technology is superior. That's why Microsoft is pushing for MVC and has slowly moved away from web forms (even internally). No other full stack setup does it that way. I can easily go from Django to Rails to Symfony to ASP.NET MVC because the core ideas and basic setup are the same. In fact, I learned on ASP.NET MVC first, then went to Symfony. Web forms? Completely alien and weird and not standard.
If I weren't so rusty, yes, I could do it in a day. No, I'm not bragging or lying. Web forms is fast for you because you're used to it, not because the technology is superior. That's why Microsoft is pushing for MVC and has slowly moved away from web forms (even internally). No other full stack setup does it that way. I can easily go from Django to Rails to Symfony to ASP.NET MVC because the core ideas and basic setup are the same. In fact, I learned on ASP.NET MVC first, then went to Symfony. Web forms? Completely alien and weird and not standard.
"I was thirsty for everything, but blood wasn't my style" - Live, "Voodoo Lady"