Image not showing in codeigniter 4

I would hard a guess and think the image is being called from the public folder... If so and you really want to use the WRITEPATH folder then try using s relative path which should be converted to an URL:

<img src="../writable/uploads/avatar/avatar_1.jpg">

I will try it to make sure it works when I am back on the desktop.

As mentioned far better to group all callable files into a common folder:

/public_html/assets/
css/
img/
js/
svg/