Not going to deal with image (word) navigation. Merely asking why image instead of the word... which is better for both user (accessibility) and search engines. Might want to do a rethink in that regard (and solve a LOT of problems all at once).
Note: this is not a solution, it is an observation regarding general use and works cross-browser (all of them).
And, before I forget! Welcome to Webmasterworld! Remember me as the crotchety old curmudgeon.