First off, how wonderful that you got your issue resolved by the designer! It never hurts to ask.
The failed message is often because the file size of the picture is too big. I have an old school digital camera and I reduce my images here:
https://www.reduceimages.com/
No affiliation but quick and easy and does not set off my various filters and protections. I just use their defaults.
There are other picture posting tips stickied to the top of the Help forum here
https://www.quiltingboard.com/qb-help-center-f27/