Images don't require any specific key commands to access. Just like other content they will be announced as you move through the page.
What is worth looking at however is how the various states will be handled by NVDA as this will help you recognise when there is an issue.
Activity - images and alt text
Using NVDA, move to the images below.
The first image has no alt attribute at all and it is actually ignored, although this is not true for all screen‐readers (for example Voiceover on Mac will read out the file name).
On the second image, this has been marked up as if the image is purely decorative. The blank alt attribute here allows the screen‐reader to treat it purely as decorative so NVDA will ignore it entirely.
The final image has some meaningful alt text added which is read out as NVDA reaches it.
What is actually used as alt text should really be dependent on the context of the image.
Key takeaway
Make sure images have appropriate alt attribute content.