Add extra comments about data types

src/main/java/edu/illinois/library/cantaloupe/image/Metadata.java

@@ -141,6 +141,8 @@ private void readOrientationFromEXIF() {
                     // According to spec the orientation must be an unsigned short (16 bit)
                     // However, we have seen exif data in the wild with LONG and SLONG types
                     // Thus to be lenient we accept either and convert to int (github issue #548)
+                    // It could also happen that 'value' is in fact a Java Integer even if the
+                    // exif data type is LONG or SLONG, so we need to check for that as well.
                     if (value instanceof Long) {
                         orientation = Orientation.forEXIFOrientation(Math.toIntExact((long) value));
                     } else if (value instanceof Integer) {