Image string function in PHP

My understanding of the image string function is this, that it allows the
display of text in Graphics
As per the parameters it receives:

ImageString($image,6,$xpos,$ypos,$out,$col)

these params:
1. name of thew image to write on
2. size of the font
3. X co-ordinate of the first letter of the string
4. Y co-ordinate of the first letter of the string
5. The string to be printed
6. The colour to display the string in.

My Question is can the "string to be printed' be used as an <a> to a frame,
and just say I was to design a frame that had images with text, how could I
put the primary key to a mysql table in what is passed into the php frame I
refence from the anchor.

basically How can I get from a clickedon image in frame one to getting the
primary key from this and then passing it into frame two fro a data base
lookup, I have the mySql side of it and displaying the PHP down pat, just
getting the key across from a clicked on image (HTML and javascript)
Is the target attribute of the <a> tag enough or is there another global
type variable I can store a key in and pass it into the php which then does
the lookup.

Can you comment on this plaease
<a href=\"frame2.php?content=$key\>"$value[0]</a>
is this a better method of passing a variable into php than trying to use
TARGET ?


Any help greatly apprecated, I'm trying to do too much at once with my
limited understanding, and just going in circles.

Thanks