What is the recommended size for an image on our website? What is the largest image size we can use without being penalised by Google? Thank you.

We want to work out if it is beneficial to use links pointing back to categories (higher up in the structure) on our website product pages. For example, our Aria Dress by Jadore is found through the path: Home > Bridesmaid > Full Length Bridesmaids Dresses > Aria Dress In the product description for the Aria Dress, is it beneficial to include internal links pointing back to higher branches in the website structure .e.g. the Full Length Bridesmaids Dresses category page, the Bridesmaid category page, as well as linking back to the 'Jadore' page? Will doing this for every dress (linking back to category page), improve the SEO of these category pages? How many internal links is too many to include on any given product description? Is it more important to ensure a direct link to every single webpage so that they can be reached by Google, or to include links in both directions .i.e. from Home > Product Category > Product, as well as from Product > Product Category? Thank you.

is it best to have in the H1 tag 1. just our website address 2. combination of website address followed by short keywords about our website

On our website we have some invisible/hidden categories on our site. Can anyone advise whether these are harmful in terms of SEO?

We have 2 sites that have been set up slightly differently. On 1 site we have the Company name in the H1 and the product name in the page title and H2. On the other site we have the Product name in the H1 and no H2. Does anyone have any advise about the best information to have in the H1 and H2