There are a couple of questions I'd ask before making recommendations: You said you will use the system for "office work and some image editing (Photoshop). No gaming." Does this mean the system will be in an office? Or is it for your home?
If office, then I'd say the fanless system you're considering is overkill, because the ambient background noise in most offices is high enough that a quiet fan-cooled system will be inaudible anyway.
If it is for home use, then the noise caused by the vibration of the HDD is the single #1 problem with all the fanless chassis used by Pyrotech. The last time I examined them, neither the Zalman nor the mcubed cases had good HDD mounting solutions built-in. You really want to ask about this: In the absence of any other noise, the HDD vibration noise will definitely be audible and -- at least for me -- annoying. It's usually more annoying than having that HDD noise masked by the whooshing broadband sound of a smooth fan, even if the latter is a bit louder.
Which is one reason you might want to consider a SSD, but that's a very expensive proposition for systems that are already expensive. And having a regular HDD with an SSD does not make sense acoustically, as the former's noise will override the latter's silence.
The Antec Solo case systems (like pyro bas silent) can offer the best balance of low, benign-quality noise and modest price. This assumes the built-in elastic cord suspension is used for the HDD mounting, the main case fan is changed for a quieter one, and the CPU heatsink/fan is also very quiet. The system specs don't cover all these details; you'd need to ask. (Most modern HDDs can be used without much concern for noise, as the elastic cord suspension does very effective damping.) Here's an example of a very quiet Solo-based system: Model One by End PC Noise
Keep in mind that silence is in the details. It requires good planning, good component choices and excellent attention to details of execution to make a truly quiet computer.
An Aside: All this makes me think we should set up some system integrators in the EU to offer SPCR-certified quiet PCs. The distance makes it difficult but not impossible. Perhaps our EU regulars can offer likely candidates?