(PECL ps >= 1.1.0)
ps_open_image — Reads an image for later placement
$psdoc
   , string $type
   , string $source
   , string $data
   , int $lenght
   , int $width
   , int $height
   , int $components
   , int $bpc
   , string $params
   )
    Reads an image which is already available in memory. The parameter
    source is currently not evaluated and assumed to be
    memory. The image data is a sequence of pixels starting
    in th upper left corner and ending in the lower right corner. Each pixel
    consists of components color components, and each
    component has bpc bits.
  
psdoc
     Resource identifier of the postscript file as returned by ps_new().
type
     The type of the image. Possible values are png, jpeg, or eps.
source
     Not used.
data
     The image data.
length
     The length of the image data.
width
     The width of the image.
height
     The height of the image.
components
     The number of components for each pixel. This can be 1 (gray scale images), 3 (rgb images), or 4 (cmyk, rgba images).
bpc
     Number of bits per component (quite often 8).
params
     
Returns identifier of image or zero in case of an error. The identifier is a positive number greater than 0.