Hi @boris.hernandez,
This was one of my more ambitious projects and I think I got a little zealous with the blocks. Looking at it now, I would probably re-do much of the viewer part. I concentrated more on a file-picker that doesn’t use Cloudinary at all but that is another project entirely.
I am glad you managed to use the filepicker and upload to your cloudinary account but in order for me to consider your issue, I really need to know if you are populating the firebase database node as you upload. It is only then that you can start to look at fetching the cloudinary urls from the RTDB and display them in some arbitrary viewer in Thunkable.