Google Photos keeps syncing photos and I cant disable it

Question

I've been using Gmail for some while and my storage has been around the 3.5GB out of 15GB.
After using Google Drive recently to transfer some files, I've somehow and inadvertently, 'enabled' Google Photos meaning that photos are 'syncing' form 'somewhere'. My storage has rapidly reached 15GB as a result. 
I've spent several hours deleting literally hundreds of pictures from Google Photos. I get the storage down to 12GB or so but it keeps creeping back up to 15GB and loading photos back in.
I'm using a laptop, I don't have the Google Photos app on my iphone or ipad but I can't see a way, anywhere, in the Google settings on the laptop to allow me to disable Google Photos. I really don't want to be driven down the Google additional storage option as I already have OneDrive (where the photos are stored normally).
If anyone can help, I'd be so grateful thanks!

PeteranDi · Accepted Answer

The photos must be coming from somewhere, either a mobile phone, or Drive for desktop.
Can you upload a screenshot of one of the recent photos showing the (i)nfo field as per the screenshot online.

PeteranDi · Accepted Answer

Good luck, get back to me if you have any more questions.

PeteranDi · Accepted Answer

Thanks, it looks like you have Drive for desktop installed on your computer. If you go into preferences and click on the folder you are syncing then remove the tick from the Backup box they will stop uploading.