First on your form add an image as a placeholder. Do this by selecting the Image button (near textboxes and combos etc)
Drag it over the area you want to cover. It will ask you to select an image. I'd choose whatever picture you want the default to be. (I'm pretty sure it forces you to have
some image in there, though I could be wrong - you might also be able to use an unbound object frame, anyone?)
Now change the Control name of this image to something better than Image1 or whatever.
Now on your combobox, use the "AfterUpdate" Property. In there put code that could look something like this
Code:
Select Case [YourComboBox].Value
Case "Choice 1"
[YourImageName].Picture = "C:\YourPathToPicture\YourPicture.jpg"
Case "Choice 2"
[YourImageName].Picture = "C:\YourPathToPicture\YourPicture2.jpg"
End Select
You can of course have a bajillion ways to choose the image other than a select case, but that's what I normally use for comboboxes
The important property here is the .Picture