1. Liebesgruß
Actually consisting of two words: Liebes - gruß
Meaning: message of love
A small message (SMS, letter, phone call,...) used to assure your sweetheart of your love.
Example: Ich schicke Dir einen kleinen Liebesgruß!
Liebesbrief: love letter

2. Werbedia
Again consisting of two words: Werbe - dia
I had to think a bit myself here...
Meaning: promotional slide
One of these little photos which you can project against the wall,
containing promotional material in this case / advertizing a certain good
or travelling to a certain destination for holiday.

3. Filmvorstellung
You have a preference for two-word words today: Film - vorstellung
Meaning: screening / cinema showing
The event / process where a movie is shown
More rarely: An event where a (usually new) movie is introduced (e.g. on a film festival). But then it usually requires that the director and/or some of the actors are present as well.
Example 1: Die Filmvorstellung beginnt um 20:00. (usually the first interpretation)
Example 2: Wir laden sie herzlich zu unserer Filmvorstellung ein. (both interpretations)
Example 3: Wir laden Sie herzlich zur Vorstellung unseres Filmes ein. (only second interpretation)

Example: Vor der Filmvorstellung wird es eine kleine Show mit Werbedias geben, die Ihnen einen Urlaub in Rußland schmackhaft machen sollen. (Before the movie there will be a short show with promotional dias which should encourage you to spend your holiday in Russia.