Photo Resize in PicoCMS Blog?

hello to other PicoCMS users, I have a question before installing/using PicoCMS : I want to publish a blog with pictures and some text around. If I chose the blog “built in” template, what about photo size ? Is there something in Pico for Nextcloud that generate previews like Nextcloud Photo does , or must I manually generate all small-sized photo and manage the links to full size photo in my Markdown pages ?

thanks for your help,