Resize product image for individual category

Hi,

There is no option for that.
You would have to force the image size based on the category with custom code added to the show_block_img file of the product view via the menu Display>Views.
You'll want to change that code:

$height = (int)$this->config->get('product_image_y');
			$width = (int)$this->config->get('product_image_x');

Hi,

In $this->categories you have an array of objects and each object contains all the data of the categories.
So if you have only one category attached to your product, then you can use that code:
echo $this->categories[0]->category_name;