Hi to everybody! My answer is:

It's possible to have different image on block title for each block? I mean an icon image near the title of the block, one for each block.

Anyone could help me?

thank a lot.

It is possible if you know how to use Smarty template.

eg) theme.html

<div class="blockTitle"><{$block.title}></div>

changes to:

<div class="blockTitle">
<{if $block.title == "Main Menu"}>
<img src="icon_main.gif" /><{$block.title}>
<{elseif $block.title == "User Menu"}>
<img src="icon_user.gif" /><{$block.title}>
<{else}>
<img src="icon_etc.gif" /><{$block.title}>
<{/if}>
</div>


And this is not a hack but a theme designing.