Quality and size (anyone know how to do it properly)?

@Herofeeder John Dope
Tue, 04 Oct 2016 17:34:07 +0000

so i noticed when i post 940px with 350 dpi on tapastic...it looks okay
but if i post the same comic on other sites like Twitter or Deviant art or 9gag .
it starts to look weird ..like you have to squint a bit, so i was wondering if im doing something wrong
do i have to put even higher DPI
or soemthing
also after i do the lineart in medibang I imm go to Phostoshop to color it (not sure if that has something to do with it changing the programs n stuff )

http://imgur.com/a/mXWwa (this is the size and the DPI )