Phtcache.bin

File Header

Offset	Size	Description
0x0	0x8	Always "1UJQ00_1"
0x8	0x4	Number of Pictures + 1
0xC	0x2	Total number of photo entries(including unused entries) stored here, this is normally value 3000 (500 on NAND).
0xE	0x2	This u16 must be < 2, this is normally value 1 (0 for NAND).
0x10	0x2	Unknown, normally value zero.
0x12	0x2	Total number of photos(used entries), excluding 2D dups.
0x14	0x2	CRC16 over the entire file with this CRC field set to zero when calculating the CRC, with initialval=0 and polynomial=0xA001.
0x16	0x2	Size of this header, must be >=0x18(this is always value 0x18).
0x18	0x98 * Number of Pictures	Pictures Property, index refereed by 3DS Camera

The phtcache.bin actual filesize must be at least the following size: hdrsizefield + totalstoredentries*0x98.

Pictures Property

Offset	Size	Description
0x0	0x04	Null-terminated file extension: MPO, JPG, or AVI.
0x4	0x8	Image file name, without the extension.
0xC	0x8	Directory name under the DCIM directory.
0x14	0x4	Time taken based on "DS epoch" (start of 1/1/2000) (UNIX+946684800)
0x1C	0x4	Time last viewed?
0x24	0x4	?
0x28	0x4	?
0x2C	0x4	?
0x30	0x4	?
0x34	0x4	?
0x38	0x4	?
0x3C	0x4	?
0x40	0x4	File size
0x50	0x18*4	4 blocks, where each block is 0x18-bytes.