In terms of Cookie Jar scenes:
View attachment 2275342
No images to change | 26 | 17% |
Complete | 43 | 28% |
Incomplete | 43 | 28% |
No progress | 43 | 28% |
Of scenes that require changes:
View attachment 2275344
Complete | 43 | 33% |
Incomplete | 43 | 33% |
No progress | 43 | 33% |
So, with 33% of the work totally done, and another 33% partially done, I estimate that the Beta number is also the progress %. So, 50%.
As far as how long you can play before reaching unmodded images, that depends on what routes you choose. Probably not very far. I had started out playing the game from the beginning and working on each scene as I encountered it, but I switched to a different system later. The newer content is often easier to change than the older content, so you may find that unmodded images decrease as you get further into the game.