Insert: Uploads a channel banner image to YouTube. This method represents the first two steps in a three-step process to update the banner image for a channel:
- Call the channelBanners.insert method to upload the binary image data to YouTube. The image must have a 16:9 aspect ratio and be at least 2120x1192 pixels. - Extract the url property's value from the response that the API returns for step 1. - Call the channels.update method to update the channel's branding settings. Set the brandingSettings.image.bannerExternalUrl property's value to the URL obtained in step 2.