For the image displaying properly, you could also change this line in style.css:
img{width:80px;height:80px;}
to
.form-group img{width:80px;height:80px;}
This will fix the image being only 80px wide, and will automatically take the maximum possible dimensions. This will also keep the right dimension on places it needs to be 80*80 (if i’m not mistaken, didn’t test that much)
For the login page not having the right title see my answer at:
https://community2.invoiceplane.com/t/title-on-login-page/1925/3?u=kreekhoorn
Here you’ll find what you need to edit and how. 
Cheers,
Kreekhoorn