Paste this in _User_MapStyles.xml and try if it works.
Code:
<ImageStyle Name="exp18_prelude_feerrott_epic01_temple" displayname="Savage Cay" zonerect="763, -52, 1085, 322">
<ImageFrame Source="images/maps/map_feerrott_epic01_temple.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp18_prelude_home_oakmyst_island" displayname="Lichveil Island" zonerect="-1177.50, -462.25, -605.39, -33.11">
<ImageFrame Source="images/maps/map_home_oakmyst.dds" SourceRect="0,0,800,600" />
</ImageStyle>