number of images viewed

I am trying to measure the number of images and perhaps the duration that images are viewed for using medialab v2006.

so what I want to achieve.
There will be a set of 20 images which particiopants are given the option to view as many or few as they like.
How can I allow them to stop viewing the images ie choose to only see 4 images and then press a button to end this part of the experiment?

An alternative would be to time how long they veiw the images ie 'spend as much or as little time viewing the images as you choose'.

I would appreciate any advice on this.

Thank you

Naomi

One solution may be to use the backimage property to display an image on the screen with a scale response item type. Using a scale response you can allow the user to continue by pressing 1, and end the session by pressing 2. If they press 2, you would simply skip to the end of the questionnaire. Does this make sense?

To save how long a user stays on an image, make sure that the option 'WriteRT' is turned on for each item. This will tell you in milliseconds how long the user viewed the image before continuing.

Does this information help out?