Random image with Cycle
You can do this in lots and lots of ways. This is 1 way without Views.

I did this for a homepage. I made 5 variables that hold FIDs for files uploaded using FAPI file_managed fapi element in an admin settings form.

Then using hook_page_build if I'm on the homepage I created a render array that simply calls theme_image using a random file id by loading my 5 variables into an array and using PHP's array_rand() to extract 1 random array value.

Lastly, if you can get this far -- and you have page caching turned on ... you'll only get 1 image ever and it'll never be random. For the render array inserted using hook_page_build you have to set #cache =&gt; FALSE within the render array so Drupal will not cache your images and it will be random every pageload.