Adding a little link button

Hi all,
there is a site i like and it has link buttons (different sizes, different configurations).
see
https://www.lovefoodhatewaste.com/about_food_waste/link_to_us.html

I would like to create a little graphic and offer the same linking ability on my site (either on a new page or in the right hand side column) –
i would like other sites to include my little linking graphic on their sites.
would anyone know if /how this could be done?
thanks in advance
wasteman
https://www.wasteman.com.au