While this doesn't sort out your zoom, you could try a little trick based on CSS & relative sizing.
If you have an image or a container that is 100px
wide, try setting it to 10em
wide (or faff with the em
amount until you find the appropriate value). Eventually, if you do this to every single dimension specified upon your site, you'd be able to actively shrink the page by changing the default font-size
. E.g. from 1em, to 0.91em.
People often use the relative sizing to allow people the flexibility of being able to shrink and grow font sizes as they want. It's not as commonly used on images (because they are by requirement, fixed in size). This needn't be the case though, and in this instance, might offer you a way out of a "full site redesign" and giving the effect of "zooming".
This might solve the problem without redesign, but may be tricky and would require a bit of testing. The way stylesheets cascade, shrinking the font a little more, element by element, might cause a few issues.