Please be advised that is recommended images with size of 1200×600 pixels
However images can have a resolution less than 5000×5000 pixels
The maximum size of the images must be less than 4.90 MB.
No more than 25 images may be uploaded.
If you find it easier to send the images to the next firstname.lastname@example.org mail; if these are heavy you can also do through wetransfer or dropbox.