There's currently no way that I know of to transfer photos from your computer to your IPhone but for those who need information on how to transfer photos from their Iphone to their computer here's how to do it.
Not sure what operating system you're using but if you're using windows 10 operating system on your laptop you should have a settings app in window 10.
Open the settings app and click on the phone option then click on add a phone and a new window should appear where you can select your country code and phone number.
You should be able to connect your Iphone to your laptop or desktop windows computer either via WIFI or USB cable.
Here's how to connect your IPhone to your Windows Laptop without Itunes.
Connect a USB cable to the Iphone and to your laptop computer and then go to the photos app on your laptop, you can find the photos app by typing photos in the search bar located at the lower left corner of the screen on windows 10.
And then to transfer the photos from your laptop to your computer click on the import button.