Replace: show_form_header("thumbnailer.php", "createthumbnails", "form");
echo "<table cellpadding=\"0\" cellspacing=\"0\" border=\"0\" width=\"100%\"><tr><td class=\"tableborder\">\n<table cellpadding=\"3\" cellspacing=\"1\" border=\"0\" width=\"100%\">\n";
echo "<tr class=\"tableseparator\">\n<td class=\"tableseparator\"><input name=allbox type=checkbox onClick=\"CheckAll();\" checked=\"checked\"></td>\n<td class=\"tableseparator\">".$lang['field_image_name']."</td>\n<td class=\"tableseparator\">".$lang['field_image_file']."</td>\n<td class=\"tableseparator\">".$lang['field_category']."</td>\n</tr>\n";
echo $imgs;
show_table_separator($lang['convert_options'], 4);
echo "<tr class=\"".get_row_bg()."\">\n<td colspan=\"2\"><p class=\"rowtitle\">".$lang['convert_thumbnail_dimension']."</p></td>\n";
echo "<td colspan=\"2\"><p><input type=\"text\" size=\"$textinput_size\" name=\"dimension\" value=\"100\"></p></td>\n</tr>\n";
echo "<tr class=\"".get_row_bg()."\">\n<td colspan=\"2\" valign=\"top\"><p class=\"rowtitle\">".$lang['resize_proportions_desc']."</p></td>\n";
echo "<td colspan=\"2\"><p>";
echo "<input type=\"radio\" name=\"resize_type\" value=\"1\" checked=\"checked\"> ".$lang['resize_proportionally']."<br />";
echo "<input type=\"radio\" name=\"resize_type\" value=\"2\"> ".$lang['resize_fixed_width']."<br />";
echo "<input type=\"radio\" name=\"resize_type\" value=\"3\"> ".$lang['resize_fixed_height']."<br />";
echo "</p></td>\n</tr>\n";
echo "<tr class=\"".get_row_bg()."\">\n<td colspan=\"2\"><p class=\"rowtitle\">".$lang['convert_thumbnail_quality']."</p></td>\n";
echo "<td colspan=\"2\"><p><input type=\"text\" size=\"$textinput_size\" name=\"quality\" value=\"75\"></p></td>\n</tr>\n";
show_form_footer($lang['create_thumbnails'], "", 4);
with: show_form_header("thumbnailer.php", "createthumbnails", "form");
echo "<table cellpadding=\"0\" cellspacing=\"0\" border=\"0\" width=\"100%\"><tr><td class=\"tableborder\">\n<table cellpadding=\"3\" cellspacing=\"1\" border=\"0\" width=\"100%\">\n";
echo "<tr class=\"tableseparator\">\n<td class=\"tableseparator\"><input name=allbox type=checkbox onClick=\"CheckAll();\" checked=\"checked\"></td>\n<td class=\"tableseparator\">".$lang['field_image_name']."</td>\n<td class=\"tableseparator\">".$lang['field_image_file']."</td>\n<td class=\"tableseparator\">".$lang['field_category']."</td>\n</tr>\n";
echo $imgs;
show_table_separator($lang['convert_options'], 4);
echo "<tr class=\"".get_row_bg()."\">\n<td colspan=\"2\"><p class=\"rowtitle\">".$lang['convert_thumbnail_dimension']."</p></td>\n";
echo "<td colspan=\"2\"><p><input type=\"text\" size=\"$textinput_size\" name=\"dimension\" value=\"".$config['auto_thumbnail_dimension']."\"></p></td>\n</tr>\n";
echo "<tr class=\"".get_row_bg()."\">\n<td colspan=\"2\" valign=\"top\"><p class=\"rowtitle\">".$lang['resize_proportions_desc']."</p></td>\n";
echo "<td colspan=\"2\"><p>";
$resize_type_1_checked = ($config['auto_thumbnail_resize_type'] == 1) ? " checked=\"checked\"" : "";
$resize_type_2_checked = ($config['auto_thumbnail_resize_type'] == 2) ? " checked=\"checked\"" : "";
$resize_type_3_checked = ($config['auto_thumbnail_resize_type'] == 3) ? " checked=\"checked\"" : "";
echo "<input type=\"radio\" name=\"resize_type\" value=\"1\"".$resize_type_1_checked."> ".$lang['resize_proportionally']."<br />";
echo "<input type=\"radio\" name=\"resize_type\" value=\"2\"".$resize_type_2_checked."> ".$lang['resize_fixed_width']."<br />";
echo "<input type=\"radio\" name=\"resize_type\" value=\"3\"".$resize_type_3_checked."> ".$lang['resize_fixed_height']."<br />";
echo "</p></td>\n</tr>\n";
echo "<tr class=\"".get_row_bg()."\">\n<td colspan=\"2\"><p class=\"rowtitle\">".$lang['convert_thumbnail_quality']."</p></td>\n";
echo "<td colspan=\"2\"><p><input type=\"text\" size=\"$textinput_size\" name=\"quality\" value=\"".$config['auto_thumbnail_quality']."\"></p></td>\n</tr>\n";
show_form_footer($lang['create_thumbnails'], "", 4);
... and you have values from gallery config, not some fixed figures, as it is now.