When I'm at home alone or with family I like taking pictures but when the picture is don being taken there are spirit balls in the background what does that mean? Does that mean that there is someone living in my home?

Can you post an example picture?

It means that the way that you took the photo made a circular defect on the film - probably due to a reflection, or light catching dust particles or something similar.

Hi, haddock!

As has already been mentioned, dust could be a factor that you might want to consider here.

There is considerable discussion about this on a number of sites that can be found via clicking on the following link.

Orbs Dust on the Lens - Google Search

Thanks!