Q:

Product image zoom on mobile device - modal or new window?

On a product web-page on a mobile device (in this context this is limited to mobile phones and phablets. Tablets and desktop machines are exempt) the main product image is still quite small. Implementing a "zoom" feature. Which is considered better practice -

open a modal window showing a scroll-able full-sized image,

or

open a a new tab (i.e. use target="blank")?

A:

I would consider a a modal window the better practice. It keeps the user on the same page, it just gives them a quick glance. 
If a new tab sporadically opens up, they might get confused and try to hit back (Which won't work in a new tab) then get frustrated. I also never liked moving my mouse all the way to the top of the page just for this small interaction (Maybe I'm just lazy then haha). 

