The use of main Events module as a summariy of several subcalendars does not work that way. The main calendar has it's own set of events with the sum of all subcalendars. If you enter events in the main calendar, they do not end up in the subcalendars. So this way you have to enter the right event in the right calendar.

You might want to try the other way around: have 1 calendar on the main page and use this as a subcalendar on all other pages, while filtering the display of the other calendars via the URL of the page. See the documentation on CodePlex or use the filter setting in de General settings of the "other" calendars.

If you want to display images in the list view, you have to use the REPEATER control in the list view, not the GRID (this last one is still there for backward compatibility). Select the repeater in the Display settings of the module.

In the List view body template you now can use the token for the event image ([event:eventimage]). Templates are edited in the settings of the module (last tab). For a complete list of all tokens, look here.

Please remember that both the master calendar as well as the subcalendar have there own set of templates