Which technique of creating emphasis is in primary use in this painting?

Perspective to show and create the emphasis in this painting

This has to be at least 20 words so :

Photography has changed its subject matter quite a lot over the past few years. in the 1800's, it was considered normal for families to have  post mortem photos of their loved ones, and now that would be completely unacceptable. i think that photographers have always pushed boundaries and have been eager to capture everything, it is just society that changes their boundaries.