How to get url of Active Storage image
For my User which has_one_attached :avatar I can get the url in my views with <%= image_tag url_for(user.avatar) %>.So, in controller I would use just url_for(user.avatar)
For Category which has_one_attached :image:
url_for(category.image)
Also try @object.image.service_url. This will give you the url where the image is saved. I.E. url to amazon s3 storage.
Please follow this for fetching images( in case if you are using has_many_attached)
Model.images.map{|img| ({ image: url_for(img) })}