To add or change your channel's image or cover photo:
Go to the channel page you want to update.
Click the pencil icon in the upper right corner of the channel card.
On the editing page, select "Channel Info".
The first two fields are for "Channel Image" and "Cover Image".
To change an existing image, click "Delete Photo" to remove it.
Click "Upload" to add a new image and select the photo from your device.
Make sure your images follow the recommended sizes for the best appearance:
Channel image: 400x400px
Channel cover image: 1200x400px