epub & cover image

When I compile an epub with a cover image, it fails validation.
For example here http://validator.idpf.org/

Are there certain rules for cover images?

iBooks on mac seems to accept cover images, but iBooks on iPad is more strict.
This lead me to using a validator to find out what the issue was.

ebookcoversize.com

I tried that size and it still failed.

As a test I created a new project in Scrivener, selected novel template.
I then compiled an epub, and ran it through the validator. It failed.
There is something about the validator or something about the compiled epub.

Okay, so you didn’t try to upload it to iBookstore?

No, I am trying to get it to view on ibooks on an ipad.
I can view it on a mac.
It won’t validate. I figure the ibooks/ios version is more stricter than the mac version.

Without knowing anything about your image, who would know?
I had Scrivener fix the cover and it simply worked as expected.

The image was to the dimensions required.

The test I mentioned, used the image from the standard scrivener template.
I was surprised the validator did not accept it.

Just for the record, this checkbox produces a technically invalid ePub file, for the purposes of making the book look nicer on Apple’s little “shelf” display modes when sideloading. You wouldn’t want to use it for anything other than that. As noted in the user manual for the Cover compile option pane, pg. 372: