Randomisation of photos and texts

URL of experiment:

Description of the problem:
Hi, for my study I have three different conditions that I want participants randomly assigned to. Firstly, I need the participants just to see the text with no photo and for the other two conditions the participants will be presented with the same text but with two different photos. If I could get a bit of guidance with how to go about it, I would really appreciate it!!
Thank you,
Alice