I am writing a minor mode which involves fetching some pictures from url and displaying them, but some of them are way too big to fit an emacs window.

**How could I manage to limit the visual size of the displayed picture ?**

For now I am using something like

`(insert-image (create-image pic nil t))`

for display, where pic is a jpeg image raw data as a string.

I spent a lot of time browsing google and couldn't find a tutorial, docs or a code example that would help me rescaling my images.  

The [GNU Emacs Lisp reference](https://www.gnu.org/software/emacs/manual/html_node/elisp/Images.html#Images) is quite obscure and confusing and doesn't contain much examples.