Cloud Vision API is a service that allows you to analyze images using pre-trained machine learning

models1. You can use Cloud Vision API to perform various tasks, such as face detection, text

extraction, logo recognition, and object localization1. Object localization is a feature that allows you

to detect multiple objects in an image and draw bounding boxes around them2. You can also get the

labels and confidence scores for each detected object2.

By sending user-submitted images to the Cloud Vision API, you can use object localization to identify

all objects in the image and compare the results against a list of animals. You can use

the OBJECT_LOCALIZATION feature type in the AnnotateImageRequest to request object

localization3. You can then use the localizedObjectAnnotations field in

the AnnotateImageResponse to get the list of detected objects, their labels, and their confidence

scores. You can compare the labels with a predefined list of animals, such as dogs, cats, birds, etc.,

and determine whether the image has an animal or not.

This option is the best for your scenario, because it allows you to automatically and in near real time

detect whether each uploaded photo has an animal, without requiring any manual labeling, model

training, or model deployment. You can also prioritize time and minimize cost of your application

development and deployment, as you can use the Cloud Vision API as a ready-to-use service, without

needing any machine learning expertise or infrastructure.

The other options are not suitable for your scenario, because they either require manual labeling,

model training, or model deployment, which would increase the time and cost of your application

development and deployment, or they use object detection models, which are more complex and

computationally expensive than object localization models, and are not necessary for your simple

task of detecting whether an image has an animal or not.

Reference:

Cloud Vision API | Google Cloud

Object localization | Cloud Vision API | Google Cloud

AnnotateImageRequest | Cloud Vision API | Google Cloud

[AnnotateImageResponse | Cloud Vision API | Google Cloud]