re:
Hi, welcome to the iMore forums.
it depends on your settings on your iPhone.
if you have iCloud enabled, and also the iCloud-photolibrary enabled, then your photo's will be backed up to iCloud.
you can find those in the settings under 'iCloud'.
also there is a tab under the Photo's settings to enable/disable the iCloud-photolibrary (actually it's the same options there as via the iCloud settings).
if that's all enabled. then check the same settings on your iPad, turn them on if needed and your photo's will download to your iPad.