Where are the image src and descriptions coming from? If you are using a server-side script to retrieve these details from a database, file or folder, then constructing and populating a multi-dimensional array within a loop is the way to go.
If the details are fixed then you would just hard-code the array:
Code:
var imgDetails = [];
imgDetails[0] = [ "path/image1.gif", "Some great description."];
imgDetails[1] = [ "path/image2.gif", "Some other great description."];
// etc.
// details are retrieved as:
imgDetails[0][0]; // the first image path
imgDetails[0][1]; // the first description
// the number of images can just be set in stone, or read using length:
var imgLength = 10; // or
var imgLength = imgDetails.length;