Greetings,
We have reviewed your requirement as well as attached image which explain how you want it.
So here is our understanding of the same.
1. user select the design and based on that it should update the agenda image [based on selected design]
2. Based on that it should also update the price.
Now we have query about,
"But as if it were a mosaic of images, that is, each option has a "hole" for your photo, so you do not have to generate all the matrix of possibilities."
Would you please explain more on that?
Lets have a discussion here on chat so we can understand your need better.
We have experience building configuration based products and customization so we will be able to help you with this.
We have got total 15 years of experience on eCommerce & cart development as well as mobile apps development.
Thank you for considering us.
CWE