Are there pictures/paintings of Nirvana?

Although not quite nibbāna, I will contribute a drawing inspired by the experience of the base of neither perception nor non-perception by Tina Rasmussen, student of Pa Auk Sayadaw.

Only conceptual ones, IE only artists interpretations.

As others have mentioned, Nirvana is not a type of heaven, it's more of an extinguishing of conditioned things. It wouldn't make a very good picture. However Buddhism is not without its heavenly places. Some schools of Mahayana Buddhism have a Pure Land practice or consider the Pure Land to be a destination on the way to becoming a Buddha. Both the descriptions and depictions of the Pure Land are quite lovely.

Moreover, Shariputra, in that Buddhaland there is always divine music and the ground is yellow gold. In the six periods of the day and night a heavenly rain of mandarava (white lotus) flowers fall, and throughout the clear morning, each living being of that land, offers sacks full of the myriad of wonderful flowers, to the hundreds of billions of Buddhas in the other directions…

Shariputra, in that Buddhaland when the soft wind blows, the rows of jeweled trees and jeweled nets give forth subtle and wonderful sounds, like one hundred thousand kinds of music played in symphony. The hearts of all those who hear are naturally inspired with mindfulness of the Buddha, mindfulness of the Dharma, and mindfulness of the Sangha… Source: http://cttbusa.org/buddhism_brief_introduction/chapter7.asp

There are depictions of after-lifes (e.g. heavens and hells etc.).

However Buddhism teaches that these too are impermanent and not ultimately satisfying.

Nirvana is meant to be instead of afterlives such as those. It supposes a turning away from form, from sense-impressions, and from mental imaginings (and so I don't see how to depict it as a picture).

If you need an equivalent, an equivalent might be a representation of the Buddha (there are many pictures of that). Or the only other pictorial symbol I can think of, that's sometimes used to represent enlightenment, is the Ensō.

On traditional bhavachakra images, Nirvana in its "peace of mind" aspect is symbolized by the full moon.

While sentient beings down in the realms of Samsara are busy chasing desires and experiencing fruits of their own actions, Buddha points his finger at the moon as if saying: "if only you could let go of your attachments, you would get it right here and now":

Nirvana isn't a heaven, but a state or condition where there is no death, because there is also no birth, no coming into existence, nothing made by conditioning, and therefore no time.

See Wikipedia - Nibbana

It isn't a place of pleasures, like heavens typically are, but a state of no becoming, no dualities like pleasure and pain. It neither is, nor isn't.

In a famous passage in the Nibbana Sutta (Udana 8.1), the Buddha states:

There is that dimension where there is neither earth, nor water, nor fire, nor wind; neither dimension of the infinitude of space, nor dimension of the infinitude of consciousness, nor dimension of nothingness, nor dimension of neither perception nor non-perception; neither this world, nor the next world, nor sun, nor moon. And there, I say, there is neither coming, nor going, nor stasis; neither passing away nor arising: without stance, without foundation, without support [mental object]. This, just this, is the end of stress (dukkha; suffering)

Does that mean there are no heavens in Buddhism? Not like the Christian idea, as a final destination, no.

However, there are realms (ex. Trayatimsa) which are more pleasurable than earth, where one can with enough merit be reborn and eventually die to be reborn again, ad inifinitum till Nirvana i.e. cessation. See Wikipedia-Buddhist Cosmology

Here's an artist's imagination of Trayatimsa realm, however there can be no picture of Nirvana. (Image source: Wikimedia-commons)

EDIT:

Considering it some more, I think the abstract expressionism of the Zen Ensō or circle is what you want.

The ensō symbolizes absolute enlightenment, strength, elegance, the universe, and mu (the void). It is characterised by a minimalism born of Japanese aesthetics.

Source: Ensō - Wikipedia