You can delete custom images that you no longer require. To ensure successful deletion, check that you do not currently have any ECS instances created from this custom image.
To delete a custom image, perform the following:
Log on to the ECS console.
Click Images in the left-side navigation bar.
Select your desired region.
Select the image you want to delete.
Note: The image type must be Custom Image.
In the dialog box, click OK.