WPuser_78 on "alt text field question"

Hello, I have a question regarding the alt text function.
alt="" become visible but the value shown is from title field .is that normal ?

for example , the first case
*title : blank
alternative text : test

result , no alt value shown.

<img src="http://...02/IMG_68501.jpg" alt=""></img>

the second case
*title : test
alternative text : blank
result

<img src="http://...02/IMG_68501.jpg" alt="test"></img>

this time I have value for alt="test" but I don't want to be visible in the page.
Is there any workaround available to solve this ?

thanks