Learn Swedish: Jag tar fotot med min nya kamera. - I take the photo with my new camera.

Here, med is used to show the tool or instrument you are using to perform the action. Just like in English, you take a photo 'with' a camera. It acts as an instrumental preposition answering the question 'using what?'.

Why does the adjective have an 'a' at the end (nya instead of ny)?

Because it comes right after a possessive word (min). In Swedish, after possessive pronouns like min, din, or vår, the adjective always takes its 'weak' form. For most adjectives, this means simply adding an -a, no matter the gender or number of the noun.

Since it is a specific camera, why isn't it kameran in the definite form?

When you use a possessive pronoun like min, the noun that follows must be in its indefinite form (kamera), even though the meaning is specific. It is a common trap to try and use the definite form here, but possessives always pair with the bare, indefinite noun.

Could I say bilden instead of fotot here?

Yes! Both ta ett foto and ta en bild are completely natural and interchangeable ways to say 'take a picture' in Swedish. Notice that foto is an ett-word, which is why it becomes fotot in the definite form.