Given now the browsers are so powerful almost all of image conversion can be done in browser itself.
https://trustedimagetools.com/ - address this privacy concern.
It uses most open source WASM libraries and customized for performance and dynamically selects based on type of image.
It supports compress, convert, crop, resize etc.. and has built in almost all of quick presets users require.
Check out - https://trustedimagetools.com/ and let me know your thoughts.
Note - this is my second project of privacy, diffchecker.dev was my first and it is not #2 diffchecker in internet.