Post the image as normal then to take the image off again..click the `More` switch and click `Edit` on the drop,down,go down to the the image `LONG PRESS` the image and it should go grey. hit the delete key on the keyboard and the image should disappear..the change the said image just `drop & drop`an new image into the empty space and repost it
I'm not sure those steps work after a period of time. I've deleted paintings before shortly after they were posted, but at other times I could not find a way to do so. That led me to think there was a window of time for deletion.
May be worth a try, as I seem to remember Neil deleting a post just recently. Sadly, so many things have changed here since we joined eons ago. we used to have a help section and a way to communicate issues to the Corel team, but I can't even find that now.