Web life can be ephemeral. It has happened already in my relatively short journey as a writer, that some of the online publications that hosted my work are already gone. That is the case, for example, of Riverlit, the first literary magazine that published one of my poems in English. Fortunately, I took screen shots of my piece, and have ‘evidence’ of this publication for my portfolio.
Capturing the images of your published work is even more meaningful when editors have carefully paired your words with arresting visual content that you would like to preserve.
The easiest way to save web publications is to take screenshots, as mentioned. How to do it? I just press Alt + print screen keys and then paste it on a word document. I could then save it as a photo or pdf if needed. Advise on how to do screenshots from pcs here, and here for Macs.