I am wondering how to pronounce the following - mozilla, png and
gif.

I once thought that mozilla rhymed with godzilla but was corrected.
However, I have recently seen it transliterated into Tamil as
[modjilla] so I assume that came from /mod-zil-a/, not /mo-zil-a/.

Is it even realistic to expect internet terms to have a fixed
pronunciation since these terms are often learned in a text only
environment? In fact, since the internet provides such an extensive
(predominantly) text only environment, could this adversely affect
standardization of pronunciation, and cause a reversal of the
homogenizing effect of radio and TV in the last generation? Those
most affected would be the visually impaired.

Suzanne