As I read few articles and topics related to ionic2, in which they mentioned to keep your images in project level 'www' folder…
which is a good practice…
create folder name as img in project level www folder…
path for the same are YOUR_PROJECT_NAME/www/img… keep your all images here…
and give path to your images in img tag as follows:
<img src="../../../img/company_logo.png">
This works for me…and this is standard practice too…
EDIT:
when your image is located in www/img then you should reference it as img/key.png from your HTML files or as ../../img/key.png from your SCSS files.
this also worked for me…
refer this link -> Images not rendering on iOS but fine in browser