Image: __fromBytes() null and length check to avoid EXC_BAD_ACCESS li…

…me::PNG::Decode (closes #1894)

src/lime/graphics/Image.hx

@@ -1483,6 +1483,11 @@ class Image
 		__fromBase64(Base64.encode(bytes), type, onload);
 		return true;
 		#elseif (lime_cffi && !macro)
+		if (bytes == null || bytes.length == 0)
+		{
+			return false;
+		}
+
 		var imageBuffer:ImageBuffer = null;
 
 		#if !cs