I like to understand how things work…
Hello,
all of your code, assets… is in scr folder. If you build your app, for example with ionic serve, everything will created and copied into www folder. So it is the wrong place to strore things there.
You could try it. Delete contain of www folder, make ionic serve, and you see your www folder is filled again.
As mentioned above maybe you have a upper lower case problem, maybe your paths points to a folder that is not avialable at device or …
Best regards, anna-liebt