# Custom Images

### Custom Images

If a build-tool from the [Golden Image](../golden-images#macos-15-golden) should be missing or you have specific requirements for the Image your runners are using, you can customise any of our Global Images in your Professional subscription.

For detailed instructions see: [How-to: Customise Image](../how-to/customise-image).

Once your Custom Image is available you can setup a new integration using it or change the image of an existing integration.

#### Important Information

* The Custom Image will be bound to your subscription and cannot be transferred or re-used between other subscriptions.
* One custom image is included in every Professional subscription, for details refer to our [pricing page](../../../platform/pricing).
* Customising an Image will occupy a single [concurrency](../runners-and-concurrency#concurrency) of your subscription, until you finalised the image.
* Do not pre-install any other agents of your CI-provider as they might conflict with our runners.
* Do not update the macOS of the Image as it might become incompatible with CI-Engine.
  * If you have a specific need for an updated macOS version please contact our [support](https://flow.swiss/contact/#support).
