<blockquote>I have changed logo here templates/ja_medicare/images/logo.png
Now it is ok: hrvatski-prijatelji.com.hr/index.php/kontaktirajte-nas
But at frontpage I still have demo logo: hrvatski-prijatelji.com.hr/index.php
</blockquote>
HI I am assuming you are using JA Medicare quikcstart pakcage ,
that contains different template styles .
Do this Go to main menu>>Home and check which template is assigned for home menu .
Then open template manager and check the template style that is assigned on home menu
Check the logo options for this style …you can upload your logo from there .
or you can compare this style logo options with template style that is working well for you
Hope it helps