Not all naturally occurring phenomenon can or should be interpreted as a sign or omen. Unless the picture was of someone specific and of significance to you personally I would not take it too seriously.
That said there is a superstition that says a picture falling from the wall, for no apparent reason is the omen of an imminent death, however, the glass in the picture must shatter for the omen to be believed as true.
Perhaps you are experiencing an earthquake!
Rush to open areas away from buildings and braking glass, or if indoors go under door frames or strong tables.
On the other hand, perhaps the nail holding it up has just loosened over time and it fell off.
Not all naturally occurring phenomenon can or should be interpreted as signs or omens. That said there is a widely held superstition that says a picture falling from the wall (with no reason) is a bad omen, possibly of an upcoming death in the household. - however it is said the glass must break for the omen to be true.
Traditionally in Ireland it meant that someone you know was going to die
What does it mean when a picture of a deceased loved one falls from a TV stand for no reason
It most likely means that the picture was not properly secured to the wall.
nothing it means nothing
You need better picture hangers.
What does it mean when pictures fall off the wall
It means you need a new picture frame.
a candle holder that falls off a wall
No it is not. Some things just fall.
Iit means that you ( whoever knocked the photo off the wall) or the child in the photo will either Die or be hurt terribly. if u believe in superstitions you will be cursed forever
The nail was bad.
When a wedding photo falls off the wall and the glass breaks significantly brings thoughts of fear to many. There is a symbol of discord, meaning the owner of the frame must give a great big deal of thought to their relationship. If there's not enough bond, then work on it.
I would guess that the picture was not properly secured if a picture fell off the wall.