<p>I think you have trouble understanding how a basic object detection works.
I will recommend you to read this paper first:</p>

<p><a href="https://arxiv.org/pdf/1807.05511.pdf" rel="nofollow noreferrer">https://arxiv.org/pdf/1807.05511.pdf</a></p>
Can classification model be used for object detection?
<p>Let's say we have n images of cat and dog separately and we trained an image classification model to classify a new image with a probability score saying whether it's a cat or a dog.</p>

<p>Now, we are getting images that contains multiple cats and dogs in same image, how can we detect and localize objects(cats and dogs here)?</p>

<p>If it is possible, can we also depict the focus areas considered by model for prediction so that a bounding box could be drawn?</p>