Premiere Elements 10 on what computer operating system?
You should be able to right click the still on the Timeline, select Time Stretch, and then set the 5 (default) to 2 seconds.
You should be able to do this for more than one still at a Time by selecting all the clips to be involved before the Time Stretch duration set.
If you want all your 2 seconds stills for all your still imports then, before import, make sure that Edit Menu/Preferences/General and Still Image Default Duration is set to 60 frames instead of 150 frames (for a 30 frames per second system).
Please let us know if you are OK with the above information. If not, please supply more details or ask for clarification for any area of uncertainty.
I found out how to do it on Stretch time
Thanks for the follow up with the good news that Time Stretch worked for you to shorten your still image duration. Good job.
Just in case note....the shortest duration for your still is 1 frame which is the counterpart of 0.033 seconds in a 30 frames per second system. In Time Stretch it would look like 00;00;00;01.
Please do not hesitate if questions or need clarification on your Premiere Elements workflows.