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YES. And get the i7/8GB Air. It will be faster (slightly though) than the base Macbook Pro 13" for non-GPU jobs.
Depending on what exactly he is doing in Photoshop I'd also recommend maxing out the CPU and RAM. If all you do is some photo editing without 3D, then even the base air will work fine.
 
Yes, for occasional photo editing, either MBA or rMBP is sufficient. I use my MBA to do some light processing of ~30MB photos from a Canon 5D3. It's quite capable, about the performance of a 2010 iMac with a quad-core processor.

Depending on what exactly he is doing in Photoshop I'd also recommend maxing out the CPU and RAM. If all you do is some photo editing without 3D, then even the base air will work fine.
 
Depending on what exactly he is doing in Photoshop I'd also recommend maxing out the CPU and RAM. If all you do is some photo editing without 3D, then even the base air will work fine.

There's no reason to get the i7 upgrade for a MBA. It's only a few percent faster.
 
i5/i7 MBA and i5/i7 rMBP 13" all don't make much difference in CPU performance. Some programs may benefit from the optional 16GB of the rMBP 13". But if one really cares about CPU performance, then the i7 MBA is slightly faster than the base rMBP 13".

The differences between MBA and rMBP are screen quality and portability (plus more ports in rMBP). Performance is not, except for GPU-intensive programs. CPU performance is about the same, memory speed the same, and SSD the same.

BTW, i7 MBA is about 15-20% faster than i5 MBA. Still not big difference.

There's no reason to get the i7 upgrade for a MBA. It's only a few percent faster.
 
I would go with a 13" MBP if money and size is an issue (otherwise I'd do the 15"). The retina display is nice and the 13" MBP actually has a smaller footprint than the MBA.
 
You may want to consider snagging a refrubished Pro. Save some money, I have a 2012 15" Retina and it handles all of my tasks easy.
 
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