I always take photos a soon as the products arrive, and then take others when I'm reviewing in case I need a photo of something I didn't capture beforehand. So, I have hundreds of photos of products I haven't even reviewed yet.
When it comes time to writing the review, it usually takes me at least an hour, but is usually around two hours. Once the review is complete, I add my photos. Choosing the right photos, cropping them, and resizing them can take me another 30 minutes depending on how many I have and what I'm planning to include.
The LEAST amount of time I spend on a review is an hour, but the most is three at the most.