I'm afraid you can't. Even if you buy PictureNFTizer Flex Contract without the Standard Version, you will not be able to login.

Here is why:

1. PictureNFTizer Standard is the main product which is either a Monthly, Yearly or One Time Subscription.

2. PictureNFTizer Flex Contract is an Upgrade or Up-sell which adds the Flex Contract features in your PictureNFTizer  account.

3. Since PictureNFTizer Flex Contract is not independent, you will need to subscribe for the main product PictureNFTizer Monthly, Yearly or One Time subscription first. Else you can't login with only PictureNFTizer Flex Contract in your account.