Seems to be Firefox specific.
1) Is it the "New Listing" confirmation page or "Edit Listing" confirmation page or both?
2) Can you let me know if it happens with brand new images AND/OR previously uploaded images. eg. are the images uploaded from your hard drive/internet or called from images already in your "My Gallery" area.
3) Check with FF Safe Mode https://support.mozilla.org/en-US/kb...x-in-safe-mode