text to pictures using smileyfunction in fuctions.php?

Hi there,

I would like to have all the text in my posts replaced with pictures. Example: all “e”s in a text should be replaced with a link to e.gif. So i got the idea, that i could do that with the smiley-function in the functions.php. I added all the letters with the correct pictures, but now only the first letters of a word are pictures, the second chars are still text. I figured out, that the function is not able to do that, but maybe someone could help me edit it, because i am not so good at php-programming, or maybe with a nice add-on ??

Thanks.

Günther