addClass and removeClass in a switch case
I would probably add a class/something to use as a selector (in this case I added girls) to make lookup easier. You can do this in other ways such as getting the values of the actors map so do it as you will.

Also your default case is calling removeClass on a string as selection is the current contents of whatever the event is hooked to.

// Actor name -&gt; the corresponding element selector on the page
var actorsIdMap = {
    'Monica Bellud': '#Bellud',
    'Lea Seydoux': '#Seydoux',
    'Ursula Andress': '#Andres' 
}

var showImage = function() {
    var selection = $(this).val();

    if (selection in actorsIdMap) {    
        // Hide the other actors
        $('.girls').removeClass('hide show');
        $(actorsIdMap[selection]).addClass('show');
    } else {
       // Default case what do?
    }
}