If the iceberg was large enough and not far away so that after the disaster that is was photographed, maybe some passengers could have climbed onto it in an effort to survive?
Another remark beside the problems of climbing an iceberg:
A quote from Wikipedia:
Hit an iceberg 11:40 p.m. (ship's time) 14 April 1912 on her maiden voyage and sank 2 h 40 min later
After 1 hour the grade of the ship was 5°, an hour later the grade didn't change a lot (from in German Wikipedia). There was no obvious reason of a danger in the begin of the sinking.
The iceberg had two hours time to shift away until everybody realized that there is a danger. And then the iceberg was far away.
There would have been problems with people from the Titanic trying to climb on to the iceberg that resulting in the ship sinking.
To begin with, ice is slippery and from the picture you linked to, the iceberg looked like it had steep sides. Getting onto a steep sided slippery iceberg would be very difficult to do. Staying on the cold, wet, slippery sides of the iceberg would also be very difficult.
The water was very cold and anyone who was in the water would quickly succumb to hypothermia. Being cold and wet would make the task even more difficult.
If anyone succeeded in getting onto the iceberg they would succumb to hypothermia because both the ice and the air were cold; even if their clothes were dry.
There would be no way to get onto the iceberg with getting at least partially wet.
Another issue with icebergs is no-one knows how stable individual icebergs are. If the iceberg fell apart after people might have got onto it would they then find themselves in the cold ocean?