The other day I answered my question right away and thank you again.
Thanks to your advice, I was able to publish the theme image without any problems.
Up until now, I used my own image file to go directly from the “Create a version of the theme” item on this page, registered the theme image file and its contents, and completed the creation, so using the zip file is once There was not even.
However, when I examined variously based on your advice, I found that it is necessary to set the theme image and details through “Firefox Color”, and when I tried it by groping, I made a zip file according to your advice. As a result of the file verification test conducted on this page, there were no problems, and eventually we successfully released the theme image.
For me, it was a long three days, including the time for making illustrations, but it was very rich for me in three very dense days.
I’m really thankful to you! !