Error on app - code looks okay but get this image when it runs

[Leslie_K_Taylor]

[TIMAI2]

We need to see your relevant blocks when your "run" your app. (Screen1.Initialise, etc)

I see this behaviour if i do not have firebase details entered in the designer.

[Leslie_K_Taylor]

Here are the blocks

[dora_paz]

So actually you are creating a forward/backward system with images.
Set global index to 0 .
When button1 click if global index is < or equal to length of list-1 then set global index to get global index +1
When button2 if global index is > or equal lenght of list -1 then set global index to get global index -1

Try

image_test.aia (1019.2 KB)

[ABG]

Export your .aia file and upload it here.