Little help with custom decors?

I have downloaded my drawings on imgur in png format. However every time I try to submit my decors the site says the pics are not in png format. How I am supposed to link my drawings? It might be I'm just doing something wrong but i don't get what. If anyone using Imgur knows how to get the image in right way to the decor creation tool (or if you could help me to find another site to download my drawings to) please help?

imgbb.com is what i've been using and i have no problems with it! (Just make sure after you upload you click on the thumbnail and right click on the full-sized image to grab the source so you're not taking the imgbb site url.)

That worked for me! Thank you!

So i needed to make some changes to my drawings and now i should download them again to the internet... The thing is even tough yesterday imgbb worked for me, today I can't download anything there. Does anyone else have problems with imgbb or just me?