The word media is in transition right now. Technically, it is the plural of medium, but it is being used more and more as a collective singular. Many editors and style books insist that it always be used as a plural, but many others say to use your own judgment and choose the verb that "sounds" the best. Other Latin nouns have made this transition from plural to singular. Opera was once the plural of opus and candelabra was once the plural of candelabrum, but those singular forms have all but disappeared from English. Data is another Latin word that is currently making the transition from plural to collective (singular) noun.
Tvita --
You are correct to ask about this.
While the above data are useful to know, you should note that non-American English still very much does use words such as "media" in the plural. While some words are shifting, slowly, toward becoming collective singular nouns, this movement seems to be strongest in the USA. Certainly in Canada (and I'm in French Canada, on top of that!), "data" and "media" are considered plurals. And, frankly, I've never encountered "candelabra" to mean anything
but the plural.
Another example, from the local newspaper just this week, referred (correctly) to "Olympic stadia of the world." So, Latin singulars and plurals are still very strongly used in many places where a variation of English is the mother tongue.
The best advice I can give is to suggest that you explore the language development of the country in question, to see which usage is customary, and adjust your translation accordingly.
Remembering the quotation: "The medium is the message" by Marshall McLuhan might help you to remember the singular and plural of this particular word.
In the case of your specific question, about there being no "s" on "portray," note that the usage was correct. "The media portray" is a correct plural structure.
You may also want to consider that if you were to take only one aspect of "media" you'd rapidly see that the word is plural. Radio is a medium. A correct sentence for that would be: "The medium of radio . . .." To say, "the media of radio" quite frankly sounds odd and incorrect.
Thank you for posting an interesting question.