[NTG-context] Accessibility

Hi, in summer 2015 there was a thread about accessibility. Today I am looking for a solution for «images with alternate text» (https://en.wikipedia.org/wiki/Alt_attribute https://en.wikipedia.org/wiki/Alt_attribute). In HTML it looks like this: <img src="example.jpg" alt="Example text"> Is there an equivalent for this with ConTeXt? Yours, Steffen