Uploading images from a Mac to an iPad
Connect your iPad to your Mac. Open iTunes, select the iPad on the top and on the left you will find a photos menu where you can select what you'd like to sync.



Alternatively, you can use iCloud Photos, which would have to be enabled on both your iMac and your iPad, which will then sync photos over the cloud (via your internet connection). However, if you have a lot of photos, you'd might have to buy additional space on iCloud.