If I understand your question correctly, you would like to drag-trim an image event to increase/decrease its length, and see its duration update in the timeline like a video event's frame numbers?

Stills do not show frame numbers in the timeline, but you might try adding a video clip as another "take" on the still image event and just swap between the two (using the T key) when you want to drag-trim and see the duration.

Update: rather than a video clip, you can also use a generated solid color (as a take) and change its timecode to NDF.


HTH, MPH