This tag defines a bitmap character with JPEG compression.
It differs from DefineBits in that it contains both the JPEG
encoding table and the JPEG image data. This tag allows multiple
JPEG images with differing encoding tables to be defined within a
single Swf file. The data in this tag begins with the JPEG SOI
marker 0xFF, 0xD8 and ends with the EOI
marker 0xFF, 0xD9. Before version 8 of the Swf file format,
Swf files could contain an erroneous header of 0xFF, 0xD9, 0xFF, 0xD8
before the JPEG SOI marker. In addition to specifying JPEG data,
DefineBitsJPEG2 can also contain PNG image data and non-animated
GIF89a image data. If ImageData begins with the eight bytes
0x89 0x50 0x4E 0x47 0x0D 0x0A 0x1A 0x0A, the ImageData contains
PNG data. If ImageData begins with the six bytes
0x47 0x49 0x46 0x38 0x39 0x61, the ImageData contains GIF89a data.