In the layout designer that comes with mamewah, the various image fields are labelled artwork 1, artwork 2, artwork 3 etc etc. You can activate as many fields as you like and change their size and position on the screen then save the layout file.
In the mamewah/config/mame/mame.ini you express these fields like this:
artwork_image_paths [emuexepath]/snap;[emuexepath]/marquees;[emuexepath]/flyers
and so on and soforth. Mamewah allocates them in order so in the above case snap will be put in artwork field 1, marquees will be put in artwork field 2 and flyers in artwork field 3.
Also note that you only use [emuexepath] if your artwork folders are in the same folder as the emulator.exe file. Otherwise replace [emuexepath] with the actual location of the folders e.g. F:\emulation\artwork\snap;F:\emulation\artwork\mar quees etc etc.
To use the game videos you need to specify their location in movie_preview_path [emuexepath]/previews for example then you need to tell mamewah which artwork field you want the movies to display in using the movie_artwork_no setting. So if you want your movie previews to display instead of snapshots you would enter:
movie_artwork_no 1
Now if you open your mamewah.ini you will see an entry for delay_before_movie_preview. You can specify a number (in seconds) next to this entry before the movie previews display so for example if you set:
delay_before_movie_preview 5 in your mamewah.ini
and movie_artwork_no 1 in your mamewah, mame.ini
then Mamewah will display a screenshot in Artwork field number 1 for 5 seconds then start playing the movie preview file there instead.
Here is an example pic of my mamewah, mame setup with screenshots (and AVI's) in Artwork 1, Marquees in Artwork 2, Control Panels in Artwork 3 and Flyers in Artwork 4. I positioned them using the layout designer so they would appear in the correct places on the background image to make an image similar to the original cab.