No worries trust me I have had my share of problems and still do, think that's the same for everyone :D
A way you could do it, is to make a sprite that hold the images that you would like to randomly choose from, so each frame holds a photo.
This have some benefits to making them as separate sprites, its easy to randomly select between them, and you can add as many photos to it as you please very easy, without having to add any new code.
However if you plan on using animations, you shouldn't do it like this.
Since you know that you at max can get 5 photos to show and to keep it simple, you can just add 5 variables preferable to the object that handles them. If you don't have an object but just use globals you can add them there.
However just a tip, sometimes it can be a good idea to make a placeholder object in form of a 32x32 sprite which only purpose is just to keep track of something for you, instead of adding everything as globals. As the list of variables can get very long, and you cant use Booleans with globals. So having some small sprites outside the layout to help you keep track of things, wont hurt performance, but will make things a lot easier.
These 5 variable you just add the frame number of the photos that should be shown.
You can do that by randomly selecting a frame number:
Assume that the object holding you photos are called Photoholder.
Set Photo_1 = int(random(0, Photoholder.FrameCount - 1)
Set Photo_2 = int(random(0, Photoholder.FrameCount - 1)
Set Photo_3 = int(random(0, Photoholder.FrameCount - 1)
Set Photo_4 = int(random(0, Photoholder.FrameCount - 1)
Set Photo_5 = int(random(0, Photoholder.FrameCount - 1)
You let it start at 0 since frames always start at 0.
The reason you subtract one from FrameCount is due to the same reason. As it counts the actual number of frames, so if you have 10 photos it return 10. However since you want to store the frame number, and it starts at 0 you just subtract 1 from FrameCount.
Doing it like this also means that if you decide that you would actually like to use 15 photos instead of 10, you can just add them and the code will include them automatically.
When you want to show them again, you just read these values. And if there are no value it should just be ignored.
Since you know that the value will always be greater than 0 if there are a photo stored, you can just check to see if that's the case, and if so it should show the image.
If photo_1 > than 0 Show photo
If photo_2 > than 0 Show photo
If photo_3 > than 0 Show photo
If photo_4 > than 0 Show photo
If photo_5 > than 0 Show photo
So you can either just give them a default value of -1 to start with and every time you want to generate new ones you just start by setting all of them to -1, before setting the photo that should be stored.
You don't have to use a loop for this, but if you want to do it, then you could do it like this:
For 0 to int(random(1,5))
If Photo_1 = -1 then Set Photo_1 = int(random(0, Photoholder.FrameCount - 1)
If Photo_2 = -1 then Set Photo_2 = int(random(0, Photoholder.FrameCount - 1)
That should do the trick