Update product variant image

Must be a valid URL for a jpg, jpeg, png, or gif image. Maximum file size is 2 MB. If SourceURL is not provided, a file with the specified Filename must already exist for the account. IMPORTANT: Multiple product variants may reference the same image file. If a new image reuses an existing filename, the new image will be applied to all product variants that reference that filename. If unique images are required for each product variant, be sure to use unique Filename values.

Must be a jpg, jpeg, png, or gif. Maximum length is 200 characters. If Filename is specified without an accompaying SourceURL, then a file with the new Filename must already exist for the account.