not able to upload image

we love the customizer style and purchased the premium account. However it’s not possible to upload any image in any fields, nor “your logo”, nor components image area.

There is one option we found can insert image, one is on the text editor with the image icon, but when we click it, we were told to “fill in the image source”? We have no idea how. In our understanding it usually “upload” from our library or our computer.

Please help. Thank you!