(subject wouldn't allow more charactes, New Zelanders are welcome too <g>)

This is an English language question, it may sound as silly as bizarre, but I thought you could enlighten me anyways.
The reasons why others (like Americans) are not the target of this question is because I already know their answer.

Here it is:
Think of a data entry form where, among other settings, users need to specify the amount of seconds certain picture should be shown.
Which one of the following is the proper way to put it:

Show this picture for 30 seconds.

or

Show this picture during 30 seconds.

Is it "for" [a], "during" [b], both [c], none [d] the correct way?

Thanks in advance.