def prepare_request(params)
      request = process_params(params)
      request.store(:sizes, [extract_size(params.size)]) if params.size
      request.store(:format, params.format) if params.format
      request.store(:data, params.data) if params.data
      request.store(:uploader, params.uploader) if params.uploader
      request.store(:pages, params.pages) if params.pages
      request
    end
def prepare_request(params)
      request = process_params(params)
      request.store(:sizes, [extract_size(params.size)]) if params.size
      request.store(:format, params.format) if params.format
      request.store(:data, params.data) if params.data
      request.store(:uploader, params.uploader) if params.uploader
      request.store(:pages, params.pages) if params.pages
      request
    end
Returns processed metadata, and image attributes params
 @param params [Hash<Symbol>] metadata and image attributes
 @return [Hash<Symbol>] processed parameters