Pug doesn't show local image

i have a problem rendering images with pug this my app structure

app
 /mail
   /assets
      /img
        /logo.png
/templates
  mailTemplate.pug

and here's the static route in my express.js

//static files
app.use('/email/images', express.static('app/mail/assets/img'));

and here's the pug file

  img(src="/email/images/logo.png" width="112" height="43" border="0" alt="" )

the image doesn't render in the template while i'm sure that the path is right

HTML Images are defined in pug with the help of img tag. An example is given below:

//Name of the file : image.png

img(src='image.png')