I think some examples may add to this discussion. On the following picture from https://www.photonstophotos.net/Charts/Sensor_Heatmaps.htm, you can clearly spot noise contributions at lower frequencies than pixel frequency.
Also, the following pattern shows low frequency noise:
There is a difference between the technical description of the noise and the appearance to the human eye I think, as much as it is there for audio. Most humans perceive white audio noise as “high frequency”, while the spectral power distribution is flat. I think the same probably holds for spacially distributed noise. You may be familiar with the following optical illusion:
(from Wikipedia). To me, this is some hint that there is a frequency threshold under which you may not observe spacial noise as noisy, when it is “hidden” by image contents. however, I had (and probably have) to deal often with very “blotchy” noise from older digital cameras, which is really annoying and hard to get over.