Photoshop 2.5.1 writes a high-resolution bounding box comment to the EPS file immediately following the traditional EPS bounding box comment. The comment begins with "%%HiResBoundingBox" and is followed by four numbers identical to those given for the bounding box except that they can have fractional components (i.e., a decimal point and digits after it). The traditional bounding box is written as the rounded version of the high resolution bounding box for compatibility.
Photoshop 2.5 writes its image resources out to a block of data stored as follows:
%BeginPhotoshop: <length> <hex data>
<length> is the length of the image resource data.
<hex data> is the image resource data in hexadecimal.
Photoshop 2.0 and 2.5 include a comment in the EPS files it writes so that it is able to read them back in again. Third party programs that write pixel-based EPS files may want to include this comment in their EPS files, so Photoshop can read their files.
The comment must follow immediately after the %% comment block at the start of the file.
The comment is:
%ImageData: <columns> <rows> <depth> <mode> <pad channels> <block size> <binary/hex> "<data start>"
<columns> is the width of the image in pixels.
<rows> is the height of the image in pixels.
<depth> is the number of bits per channel. Must be 1 or 8.
<mode> is the image mode. 1 for bitmap and gray scale images (determined by depth), 2 for Lab images, 3 for RGB images, and 4 for CMYK images.
<pad channels> is the number of other channels stored in the file, which are ignored when reading. (Photoshop uses this to include a gray scale image that is printed on non-color PostScript printers).
<block size> is the number of bytes per row per channel. This will be equal to (<columns> * <depth> + 7) / 8 if the data is stored in line-interleave format (or if there is only one channel), or equal to 1 of the data is interleaved.
<binary/hex> is 1 if the data is in binary format, and 2 if the data is in hex format.
<data start> contains the entire PostScript line immediately preceding the image data. (This entire line should not occur elsewhere in the PostScript header code, but it may occur at part of a line.)
