Hello,
You have uploaded the logo using http and that’s why you did not see it because it was blocked by the browser. I have installed Really simple SSL plugin to fix the https issue.
Also, I tested the logo size and don’t see problem with this https://gyazo.com/718de77da4203f0184de95d2b3ed5378
Could you, please, tell me what width of the logo do you want to have?
Regards