wp-ave.com

Allows your visitors to increase or decrease font size of the “main” section of your website.
Features:
<ul>
<li>Uses jQuery to change text/font sizes</li>
<li>Shortcodes supported</li>
<li>Simple and Lightweight</li>
<li>Easy to Set Up</li>
<li>Works with all font size units</li>
<li>Uses localStorage to set font size only once across whole website</li>
</ul>

Easy Font Resize

This plugin puts a smile on my face... no issues thus far !

Actually I would love the plugin to store the font size state in a cookie (or database), so users do not have to keep resizing with every page load.

Very Good.

Allow your visitors to increase or decrease font size of the "main" section of your website.

mores

This plugin is basically just a little improvement of <a href="https://wordpress.org/extend/plugins/resize-at-upload/" title="Resize-At-Upload" rel="ugc">Resize-At-Upload</a>, a fabulous plugin by A. Huizinga.
The plugin will automatically resize an image upon upload, depending on the maximum width and height that you define. Gone are the days when you, or your client, will ruin a site’s layout by uploading a huge file with 25 megapixels. 
Be advised: there is no backup, no copy of the originally uploaded image.
The plugin uses a class originally from Jacob Wyke (www.redvodkajelly.com).

Resize at Upload Plus

Automatically resize (i.e. scale down) images after uploading. Save disk space and preserve your layout

Easy Font Resize vs Resize at Upload Plus