There’s an extension for chrome called Zoom Text Only which changes the size of only text, and preserves image sizes and webpage layout.
It adds the following hotkeys to zoom (only text):
Increase font size: Alt + -
Decrease font size: Alt + =
Reset font size: Alt + 0
It leaves all of Chrome’s regular zooming functionality alone, so the following hotkeys still work as before:
Zoom out : Ctrl + - / Ctrl Mouse-Wheel Up
Zoom in : Ctrl + = / Ctrl Mouse-Wheel Down
Reset zoom: Ctrl + 0
It changes all the fonts on a page without changing the website’s spacing, as seen below.
As a plus for anyone who might be interested, there’s even a link to the source-code on GitHub from the extension’s Chrome Web Store page.