as always: imho (!)
congratulations on shipping!!
fwiw: i have to admit, i may be getting "to old" to understand this online/service hype which took over "the it world" years ago ...
create an online-service and market it with "no upload", "local", "privacy" etc...
idk ... whats the advantage over "my" image-conversion-tool which i use heavily since decades ... if i remember it correctly, since around the late 1990ties (!) ... drummroll ... meet:
ImageMagick ~ Mastering Digital Image Alchemy
its utility called "convert" does everything a "normal" person could want for image-conversion.
its FOSS, runs locally in your terminal or GUI, produces stunning results and again: no internet needed, no privacy-concerns etc...
source-code available at
* https://github.com/ImageMagick/ImageMagick
it has lots of language-integrations etc.etc.
* https://imagemagick.org/script/develop.php
just my 0.02€
ps. if i want do develop such a converter which could run locally in the browser, i would take a look at the wasm-port of imagemagick, available here: