Firefox

Nono, you are demanding in a not nice tone from a open source community to implement some bloat workaround to fix some you-specific-issue with commercial software. You know how free and open source software works? Either you contribute something positive, or you color yourself glad you get to use something so great completely for free and stay silent. Bark at that commercial vendor that doesn't use the money from licenses + selling your soul to build something half decent! This upcoming demand-culture around things that others kindly share with wanting nothing in return pisses me off. Especially when it's not even something about the project, but carrying over unrelated cruft, instead of directing the demand to the entitiy it would be justified against.

Just build a browser extension that does the conversion. Or a script that watches a folder where you drag it into as an intermediary, and then it converts it automatically. And then share it for free, because you are a kind person! You might find a handful of people that like it. And then watch some asshat writing you a demand that "stop converting to jpeg, forever stop that! I need bitmaps for my gameboy! Just give me a SETTING where I can chooose and a nice dialog where I can pick the freaking color palette!"