should not need the permissions it asks for to do the job it does.

Damn good.

Adjusting settings, I'm using it not automatically, but with CTRL keyboard pressed (for on of numerous example of adjustments)

works well and fast.

I spent many hours switching from Chrome to Firefox only because of this extension

Byebye Chrome.
Hello Firefox and finally i have my Imagus back.
Because having a jpeg zoom when you hover your mouse over it is a "dangerous addon".

I can't use the internet without it anymore

ok

The only extension enlarges even Youtube profile images.

Search for updated versions of the sieves on "Imagus Reddit" (type into a search engine). There you should also ask your questions about problems with Imagus / Imagus Mod.

На Реддите невозможно писать комментарии, вместо этого срабатывают горячие клавиши. Только если отключать плагин на время посещения реддита

Doesn't have an easy accessible option to enable/disable on certain sites to my knowledge.