Update compare.xml

Author: dianichj

tools/image_processing/graphicsmagick/compare.xml

@@ -19,8 +19,8 @@
 ]]>
     </command>
     <inputs>
-        <param name="input1" format="jpg,png,bmp,gif,svg,eps,tiff,xcf" type="data" label="First image to compare" />
-        <param name="input2" format="jpg,png,bmp,gif,svg,eps,tiff,xcf" type="data" label="Second image to compare" />
+        <param name="input1" format="jpg,png,bmp,gif,svg,eps,tiff" type="data" label="First image to compare" />
+        <param name="input2" format="jpg,png,bmp,gif,svg,eps,tiff" type="data" label="Second image to compare" />
 
         <param argument="-highlight-style" type="select" label="Pixel highlight style">
             <option value="assign">assign</option>