The images of color, shape and material categories are generated via DALL·E which subject to the Content Policy (https://labs.openai.com/policies/content-policy) and Terms (https://openai.com/api/policies/terms/) of OpenAI.
The images of size and positional relation are generated via Image Creator from Microsoft Bing which subject to the Content Policy (https://www.bing.com/images/create/contentpolicy?FORM=GEN2CP) and Terms (https://www.bing.com/new/termsofuse?FORM=GENTOS) of Microsoft Bing.
To be updated