IE these issues are created based on bad semantics and coding in prosilver these will/should be fixed in the revamp of the theme I am working on, all images are being removed and replaced with full css/text based buttons for the navigation and as for the print, rezise, etc.. all icons are added via sprites, They have text associated with them however it is indented off the viewing area via css. This might bring up issues for the software you use, not sure how it works. However as mentioned before you can simply use Ctrl +, Ctrl - (CMD +, CMD - on MAC) to adjust the font sizes on any website in any browser.
All though I would not recommend IE as it has not yet been brought up but we may require the use of images as its backwards Compliance requires it.
If it were up to me I would completely remove the javascript and icons in the theme that simulate the ability to change the font size and recommend using the shortcuts mentioned. This would make my life a hell of a lot easier coding wise lol but I digress.