How to change image size of previosuly uploaded

According to your documentation, in the Configuration -> Main - Images you state this:

Image width and Image height : You can specify a maximum width and a maximum height for images attached to products. If the images appears to be bigger, they will be resized automatically during the upload process. If you do not want to resize images, leave these fields blank. These options only apply to the "zoomed" image of products on the product page and to the current category image on category/product listings. Note that if you change these values, the images you already uploaded in your products/categories won't be resized as this process is done at the moment you upload them.

Is there a trick to change this images size to the one stated in the height parameter?

If not, could I do this manually attacking some folder content? Which would be?

Hi,
This part of the documentation seems to be a little outdated, you'll just have to change the "height parameter" and then it will automatically create new images for your product.

It does not seem to happen with my site which runs with 2.13.

is it such a recent feature or shall I set up some parameter?

Hi,

Thanks to update to the latest version of HikaShop, as I remember it was not present in the 2.1.3