I had similar requirement to yours Zana and Adams solution above fixes the browser page title but not the titles shown on the page.
I made the following tweaks which i think answer you questions...
to show category and image titles without the "view category" and "view image" prefix modify their values in your language file so they are like this:
define('EG_SHOWCATEGORY', '%s');
define('EG_VIEW_PHOTO', '%s');
But this will leave your front page without a title so in your easygallery.html.php you can modify Adams suggestion above to fix this by making it:
if (!$row->name){
$pagetitle = EG_SHOWCATEGORIES;
$mainframe->setPageTitle(EG_SHOWCATEGORIES);
} else {
$pagetitle = sprintf(EG_SHOWCATEGORY, $row->name);
$mainframe->setPageTitle(sprintf(EG_SHOWCATEGORY, $row->name));
}
and then updating this line
<div class="componentheading"><?php echo sprintf(EG_SHOWCATEGORY, $row->name); ?></div>
to read...
<div class="componentheading"><?php echo $pagetitle; ?></div>
Hope that helps - it worked for me!
Simon