How do I link one object with another and command one of the objects to control another?

[IcyMiranda]

I want to link a parent object with an object with a photo set and have it to where when you click on the parent object, the object with the photo set changes.

[Rolig Loon]

That's a texture changer.  You will find many in Marketplace or you can look for free ones in the wiki's script library at http://wiki.secondlife.com/wiki/CatTextures that you can modify for your specific needs.

[IcyMiranda]

@Rolig Loon I would put the script into the object I would want to be the parent object and the textures into the separate controlled object, correct?

[Rolig Loon]

No.  If the controlling prim and the display prim are linked, they are parts of the same object.  You simply need to have the textures in the same prim with the script or, better yet, hard code the UUIDs of the textures in the script so that nobody can later grab the textures out of the object.  If your two objects are not in fact linked, the answer is different.  In that case, the controlling script has to communicate with a separate script in the display prim that actually does the work of changing textures.  The textures (or, again, the texture UUIDs) need to be in the display prim in that case.

Edited March 1, 2021 by Rolig Loon
typos. as always.

[Bugs Larnia]

2 hours ago, IcyMiranda said:

 I would put the script into the object I would want to be the parent object and the textures into the separate controlled object, correct?

If you want a linked controller, you can use llSetLinkTexture to change the textures. Ideally, like Rollig said, you would want to create a list of texture UUIDs, so you don't have to store the actual textures in the prim inventory. You can then loop through the list on touch and use llSetLinkTexture to change the texture and face of your linked texture prim.

I have something not unlike what you want. I put it on my pastebin.  You might need to make some changes, but it's a good starting point.