First of all read this answer to find out about how to communicate with web scripts in Unity in general:
How can I send and receive data to and from a URL, i.e. server side scripts, web services, etc?
You'll want to use the .data variable of the completed WWW object to read the file containing the URLS.
Once you have this data as a string, you'll want to split it up by whatever delimiters you have chosen. Perhaps they're separated by a certain character, with each pair separated by a newline. Or perhaps you've chosen a more advanced data format like JSON or XML.
Assuming the former, you can parse your individual items of data out using something like the method described in this answer (except instead of using a TextAsset, the text comes from the value returned by your WWW call):
putting a large amount of data into structures
Next you'll want to load the texture, which you can do using exactly the same method that you used to load the URL strings, except you need to read out the .texture variable instead of the .data variable on the WWW objecct once the call is complete.
(Referring to this as a RenderTexture is incorrect. A RenderTexture is a texture generated from the view of an in-game camera, and is often used to create realtime reflections).
Finally you might want to use this texture on a button, in a list of GUI buttons - a method do draw a list of textures like this is described in this answer which uses a for loop to draw an array of toggles.
In that example, it uses the number of children of the gameobject as the array of items, so you'd want to substitute that for your list of games.
Also you'll want to use buttons instead of toggle items for the actual GUI elements for each item.
Hope this is enough to get you on your way!