If an image spins and does not finish processing when uploading to an email template, try these steps to resolve the issue:
Refresh the page and attempt to upload the image again.
Try using a different browser or clearing your browser cache.
Ensure the image file size is not too large; images around 600x400px are recommended for emails.
Check if the image format is supported, such as JPEG, PNG, or GIF.
Attempt uploading a different image to determine if the issue is specific to the original file.