custom decor issues

I’m trying to make a custom decor, and everything very fine until it came to adding the item image. it keeps saying that ‘it’s not in .png format’ when it absolutely is. I’ve tried converted it, saving it multiple times, editing the image itself, changing the canvas size, using a different site, and lots more things but NOTHING works and it’s so frustrating!

here are images of what I want for my item and what the stupid thing keeps doing

https://ibb.co/fGFRBdq

https://ibb.co/SQ2Bd7L

https://ibb.co/Rhh1rMh

I believe it's referring to the URL itself. If you just put in https://ibb.co/fGFRBdq, it isn't in .png format, it's linking to the site.
You'll have to get the image address, which on PC is done by right clicking on the image and clicking "Copy Image Address". In this case, that's https://i.ibb.co/x8LvPqX/3-AD98-B3-E-AA86-480-D-9-BF3-B796-D264-EB89.png
With this second link, it ends in .png, which looks like the problem you're having from the screenshots you provided.

thanks so much!