This is Apple's iPod 6G SilverDB file format (BIN file)
Everything LSB first (x86-style), so mac users need to pay extra attention.


*** Header (28 bytes) ***

Datatype Description          Comment
-------- -------------------- -------------------------------------------------
int32    Magic?               Format?always 3h
int32    Character code page? Differs only for Russian language and image packs
int32    DB Table type?       1h for iamge pack, 2h for language pack
char[4]  DB Table type?       "paMB" for image pack, "mTDL" for language pack
int32    numFiles             Number of files in this pack
int32    Unknown              always 1h
int32    Unknown	      1Ch for image pack, 2Ch for language pack


*** File table format (12 bytes for each file) ***
(Applies to the image pack (SilverImagesDB.LE.bin) only)

Datatype Description Comment
-------- ----------- -----------------------------------------------------
int32    File        serial number
int32    File offset Starts counting at the address after this table,
                     so add 28+12*numFiles to this number for file offset.
int32    File        size



*** Each image file starts with a fixed header. (32 bytes) ***

Datatype Description     Comment
-------- --------------- ----------------------------
int16    Format          See next table*
int16    Unknown         always 1h
int16    Width of sprite (pixels)
int16    Flags?          I've only seen instances with just 1 bit set
int32    Unused?
int32    Unused?
int32    Height of frame (pixels)
int32    Width of frame  (pixels)
int32    Serial          Same as serial in file table
int32    Size            Same as size in file table

Note that an image describes a frame size and a (possibly smaller) sprite size.
Only the sprite contains data and what happens to the letterboxing is unknown
(maybe one of the unknown fields defines it? Where I stumbled upon letterboxing,
it was supposed to be black)



*** File format table ***

Value Description                        Detail
----- ---------------------------------- ---------------------------------------------------------
0004h 4 BPP                              Grayscale, 2 pixels per byte, first pixel in upper nibble
0008h 8 BPP                              Grayscale
0565h 16 BPP (RGB565)                    Byte2:Byte1 = RRRRRGGG:GGGBBBBB
1888h 32 BPP (ARGB8888)                  Byte4:Byte3:Byte2:Byte1 = A:R:G:B
0064h 8 BPP Paletted (256 colors max)    One int32 for palette size,
                                         then 4 times that amount of ARGB8888 bytes,
                                         then 8 BPP image data
0065h 16 BPP Paletted (65536 colors max) One int32 for palette size,
                                         then 4 times that amount of ARGB8888 bytes,
                                         then 16 BPP image data (LSB first)

Feel free to update this if you find new information.