Debes añadir esto lang/spanish/admin.php
//-----------------------------------------------------
//--- Annotation Settings -----------------------------
//-----------------------------------------------------
$lang['nav_ann_settings'] = "Annotation Settings";
$lang['nav_ann_current_conv_tool'] = "is set as an image conversion tool";
$setting['annotation_use'] = "Use auto images annotation on image upload";
$setting['annotation_mode'] = "Annotation mode<br /><span class=\"smalltext\">Select if you using text for annotation or embedding image</span>";
$annotation_mode_optionlist = array(
"text" => "text",
"image" => "image"
);
$setting['annotation_embed_image'] = "Image to embed<br /><span class=\"smalltext\">Specify full path and filename of PNG image</span>";
$setting['annotation_embed_image_opacity'] = "Embedded image opacity<br /><span class=\"smalltext\">Specify value from 0 to 100.</span>";
$setting['annotation_embed_image_bg'] = "Embedded image background color to set as a transparent<br /><span class=\"smalltext\">Define HEX value, for example #000000. Have a look at <a target=\"_blank\" href=\"color.html\">color samples</a></span>";
$setting['annotation_font'] = "Annotation font <span class=\"smalltext\"><br>Specify full path and font filename.<br>For ImageMagick & GD Lib: <b>Windows TTF</b> fonts only, for NetPBM: <b>X-Windows BDF</b> fonts only!</span>";
$setting['annotation_font_size'] = "Annotation font size";
$setting['annotation_use_shadow'] = "Use letter shadows";
$setting['annotation_shadow_offset'] = "Shadow offset (same right and down)";
$setting['annotation_image_quality'] = "Resulting image quality (in per cent)";
$setting['annotation_text'] = "Annotation text<br /><span class=\"smalltext\">You can use the following variables: <b>%N</b> - Site Name, <b>%H</b> - full Site URL, <b>%U</b> - short Site URL, <b>%S</b> - User Name, <b>%D</b> - date, <b>%T</b> - time, <b>%B</b> - line break</span>";
$setting['annotation_fill_color'] = "Annotation text fill color<br /><span class=\"smalltext\">Define HEX value, for example #FFFFFF. Have a look at <a target=\"_blank\" href=\"color.html\">color samples</a></span>";
$setting['annotation_shadow_color'] = "Annotation text shadow color<br /><span class=\"smalltext\">Define HEX value, for example #000000. Have a look at <a target=\"_blank\" href=\"color.html\">color samples</a></span>";
$setting['annotation_fill_alpha'] = "Fill color alpha blending (transparency)<br /><span class=\"smalltext\">Alpha blending value must be between 0.0 and 0.9 0.0 = no transparency</span>";
$annotation_fill_alpha_optionlist = array(
"0.0" => "0.0",
"0.1" => "0.1",
"0.2" => "0.2",
"0.3" => "0.3",
"0.4" => "0.4",
"0.5" => "0.5",
"0.6" => "0.6",
"0.7" => "0.7",
"0.8" => "0.8",
"0.9" => "0.9",
);
$setting['annotation_shadow_alpha'] = "Shadow color alpha blending (transparency)<br /><span class=\"smalltext\">Alpha blending value must be between 0.0 and 0.9 0.0 = no transparency</span>";
$annotation_shadow_alpha_optionlist = array(
"0.0" => "0.0",
"0.1" => "0.1",
"0.2" => "0.2",
"0.3" => "0.3",
"0.4" => "0.4",
"0.5" => "0.5",
"0.6" => "0.6",
"0.7" => "0.7",
"0.8" => "0.8",
"0.9" => "0.9",
);
$setting['annotation_v_alignment'] = "Vertical annotation alignment";
$setting['annotation_h_alignment'] = "Horizontal annotation alignment";
$annotation_v_positioning_optionlist = array(
"top" => "image top",
"middle" => "image middle",
"bottom" => "image bottom"
);
$annotation_h_positioning_optionlist = array(
"left" => "left image edge",
"center" => "image center",
"right" => "right image edge"
);
$setting['annotation_top_offset'] = "Top annotation margin";
$setting['annotation_bottom_offset'] = "Bottom annotation margin";
$setting['annotation_left_offset'] = "Left annotation margin";
$setting['annotation_right_offset'] = "Right annotation margin";
Puedes traducir lo que está entre " " .
Saludos.