Not counting experiences from the likes of photoshop/website building.
About 6 months of effort with lots of writing/learning/coding involved. By far the most time-consuming aspect of game development are those images/animations, no matter what program you use to create them.
In any case, for Lewd Town Adventures it resulted in quite a big release with about 2-3 hours of gameplay + 2200 images/animations or so...
The game got loads of negative feedback on the release and in hindsight, they were kind right. I could have saved myself a lot of time if I took more time studying the stuff I did as it took a lot of time for me and the game to get better. Make no mistake though, I'm still learning every day, even after many thousands of hours in. Rome is not built in one day, nor a year.
Long story short, how much time would it take right now to release a game from scratch once one is experienced? A couple of months including at least 40-hour work weeks, for a medium-sized release that would guaranteed have decent quality.
A pretty good demo could be done within a month.