Help with Images

Hi,
I am working on my store at sprybag.com
I need some help with optimizing the product images.
Here’s my Settings>Product>Display values

Catalog Images 300×300px
Single Product Image 600× 600px
Product Thumbnails 180× 180px

On the main product page on the website, the image I can see is 345x345px but the image being loaded is 600x600px
On the home page there are different carousels that serve images sized 194×194 and 135×135 but request the 300x300px image.

I am trying to reduce the page size by serving images as per requirement, what do you recommend?
When the user clicks on the product image, then a larger image (1000x1000px) must load. How do I do this?
Thanks,
Resham Panth

https://wordpress.org/plugins/woocommerce/