Is it possible to bake a single frame of a smoke simulation? I have a Photograph where I want to edit in some rendered storm clouds and therefore downloaded Blender and started to have a look into it. I'm following this tutorial to build a cloud with Cycles.

My computer isn't really fast with graphics and if I try to bake with 300 divisions and 5 high res divisions, Blender crashes.
I was able to figure out that a bake at 250 devisions and 5 high res devisions works, however it will take about a day. I only need a still render.

To reduce the baking time, I set the scene duration to a total of 15 frames, adjusted the baking frame span from 1 to 15, and I put in a temperature difference in the smoke domain settings at 0.2 because I want the smoke rise a bit to give it some texture. The still I want to render is at about frame 7.

I tried to set in the frame settings for baking 6 to 8 however then frame 7 looks like the smoke was just emitted at this frame only and not the first one. 

Is it possible to bake a single frame?
You can't bake a single frame in the middle of a simulation because blender needs to know what the state of the simulation in the previous frame was in order to compute the state for the next frame.

As an alternative, you could try using the cloud generator script for BI (tutorial), or modeling your clouds manually.