Twine Harlowe Image fade up

Twine Version: 2.6.2

Can anybody help with making an image fade up from zero to 100%?

Thanks.

When you say “fade up”, do you mean “fade in”?

Which in this context would be an image that starts off invisible, an opacity of 0, and that slowly over time becomes more & more visible until its opacity is 1.

How do you intend to display the effected image?
eg. the background of the page; an <img> element in a Passage; etc…

How do you intend to trigger the “fade-in” effect?
eg. when the related Passage gets visited; when the end-user interacts with the page; etc…