I use lightroom on my 2015 13” Pro, which is comparable to the current Air in terms of performance, with some give and take. I’m not doing heavy photo editing, but I do modest tweaks in Lightroom. I recently replaced my 10MP camera with a 24MP camera and was slightly worried how well this would work. It’s been fine, it‘s still very responsive. I have 8GB of RAM and that hasn’t been an issue either, but I would certainly consider 16. But then you’re into 13” Pro territory for pricing, comparing 256GB of each. The 8GB Quad Core Pro vs the 16GB Dual Core Air, they’re close in price, and of the two I’d take the Pro.