prevent pictures from overlapping

How can I present three pictures simulataneously without either of them overlapping each other? Also pictures will be randomized.

Picture 1: In the Event Editor, under the Input tab, have Immediately after the event is presented checked on. Nothing else should be selected. Then, under the Settings tab, both Erase screen before presenting stimulus and Keep Stimulus invisible should be selected.

Picture 2: Immediately after the event is presented should be checked on under the Input tab. Under the Settings tab, select ONLY Keep Stimulus invisible.

Picture 3: In the Event Editor, under the Input tab, select only After any response from the participant. In the Settings tab, nothing should be selected.

If the picture size is too large there will be overlapping. If this is the case change the size under the Settings tab.

The above steps explains how to display three pictures simultaneously. The next part is how to randomize these pictures.

You are going to create a Trial Variable. Under the Experiment tab you will see the Trial Variable feature, then select Screen Location. You can change the name for Screen Location here. Then, under the Levels tab, create your three locations on the screen. After this is done you may select under Level Selection, Random with No Replacement.

Now, go back to the Settings tab in the Event Editor. In the Position tab, you will select Variable under The position of the picture is. Then under Select the Variable, pick the Trial Variable you have previously created.