So - it's in colour... but old, so probably 60s/70s. A couple of images I have:

An all American family sitting in a caravan when an alien ball of light speeds past their window... rocks there caravan (which I think was a silver bullet one)

A deserted American town... main character walking through it... stops at a 50s style diner (not Yule Brenner film - tried that one!)

Final shot... alien pods along the side of a long avenue... closing (with the aliens going back inside them I think)

Hmmmmm... I would be soooo happy if anyone could work that out!

Thanks

Sounds like "Invasion of the Body Snatchers." There is a 1958 version and
A 1978 version. 1978 is in color.

Invasion of the Body Snatchers (1956) (http://www.imdb.com/title/tt0049366/) (1958)


http://en.wikipedia.org/wiki/Invasion_of_the_Body_Snatchers_(1978_film) (1978)

It sounds abit like the clip I have just watched on you tube for a film I was looking for that someone else answered for on here, "Mack and me" ?