That's why I said "subtly" and "written between the lines". War propaganda doesn't work by overtly saying "Hey, guess what, we should go to war". It builds up little by little, starting with plausibly innocent imagery (for example, picture of Country X's leader, then picture of Country X's military, then picture of Our Country's military--just that silent video montage gets into people's subconscious and starts doing its nasty work). Then it works its way up to insinuation and innuendo, then little "facts" come out here and there, then the hypotheticals. This is exactly how the US public was slowly marinated in preparation for the Iraq war.

War propaganda is in fact generally overt. It's some of the most overt propaganda there is usually.

And no, informing the populace that a country is a potential aggressor is not "war propaganda".

No, it really isn't overt usually. Not at first at least. You don't start by beating the war drums openly, it just doesn't work. It's a more subtle, gradual work of normalization before the more overt stuff.