Is it possible to store multiple key value pair array in google app engine?

I am Using python and google app engine. I have a list of images and I would like to store an external page link to each image. so right now in Google app engine the images are stored like:

contentimages:  image1,image2,image3,image4.

I would like to put the enternal link like this:

contentimages: [{image1,link},{image2,link},{image3,link}]

how can I achieve this? Quiet new to python and google app engine. Any kind of help would be appreciated. Thanks in advance