Supports various bitmap headers

lib/fastimage.rb

@@ -580,10 +580,10 @@ class FastImage
     d = @stream.read(32)[14..28]
     header = d.unpack("C")[0]
 
-    result = if header == 40
-               d[4..-1].unpack('l<l<')
-             else
+    result = if header == 12
                d[4..8].unpack('SS')
+             else
+               d[4..-1].unpack('l<l<')
              end
 
     # ImageHeight is expressed in pixels. The absolute value is necessary because ImageHeight can be negative

test/test.rb

@@ -11,6 +11,8 @@ FixturePath = File.join(PathHere, "fixtures")
 GoodFixtures = {
   "test.bmp"=>[:bmp, [40, 27]],
   "test2.bmp"=>[:bmp, [1920, 1080]],
+  "test_coreheader.bmp"=>[:bmp, [40, 27]],
+  "test_v5header.bmp"=>[:bmp, [40, 27]],
   "test.gif"=>[:gif, [17, 32]],
   "test.jpg"=>[:jpeg, [882, 470]],
   "test.png"=>[:png, [30, 20]],