There are a few services/cloud storage option and apps you can use. One of them would be iCloud, if you download it to your computer. Afaik, you can add images to iCloud on your computer, and they will sync to your other devices connected to iCloud. 5 GB of iCloud storage are free, if you need more space, you'll have to upgrade.
If you have a Gmail account, you can use Google Drive for files and photos, or Google Photos for pictures only. There's an app for both. You start with 15 GB of free storage, and it's possible to get a bit more.
Microsoft's OneDrive has an iOS app as well, and it can sync files and pictures. In July, they'll reduce their free storage space to 5 GB, so if that's not enough for you, better not use it.
And, of course, there's Dropbox too.
They all sync the images to their app.
There are also apps like this:
Photo Transfer App LITE - Easily copy, delete, share and backup pictures and videos over wifi between devices and computer by Bitwise Software SL
Photo Transfer App LITE - Easily copy, delete, share and backup pictures and videos over wifi between devices and computer on the App Store
If you search for "photo transfer" in the App Store, you'll get quite a few results.
Hope that helps.