Ich mag Bild is grammatically incorrect and translates as I like picture.
The grammatically correct form would be Ich mag das Bild which translates as I like the picture.
If it's one person you're talking to it's : Ich mag deine Musik. If you're talking to more persons : Ich mag eure Musik.
I would like to order a pizza = Ich möchte eine Pizza bestellen.
Ich mag Musik.
Ich mag dich nicht.
I like you is ich mag dich in German.
Ich mag dich sehr.
"ich mag es sehr"
"Ich mag dich" or "Ich kann dich gut leiden" would be to some that you are friendly with.
My favourite food can be translated as:Meine Lieblingsspeise ist...orMein Lieblingsessen ist...
"Ich mag diese/diesen/dieses"
Ich mag dich mein freund
If you were saying "I like horses", it would be "Ich mag Pferde". "I don't like horses" is "Ich mag Pferde nicht"