Many thanks for your answer, and good to know that you did already discussed this question.
[I didn’t tried the photo grouping functionality yet, so I hadn’t noticed that the tag was only available at item level]
I understand your concern about the UI complexity. In my opinion, and having rather complex archives (but I presume every researcher will have its own complex questions/material), a software that makes it possible to tag only pictures as a whole is not much more useful that simply using - on a Mac OS - the Finder tags. It’s already pretty common to use folders to sort a picture collection and add colourful tags to distinguish the items: Tropy is not really adding anything (the “annotate your photos” slogan seems to me a bit overrated).
I can not imagine all the uses, but think for example of someone who has a collection of old photographs: tagging people makes sense if it is possible to frame / select their faces. For now, and this is the example of your video, the annotation is used to transcribe a portion of a document, but one could imagine having several “categories” of annotations: transcription, identification of concepts or people, personal notes or comments, identification of a type of media/element (an illustration on a newspaper page, a signature, an address on a letter), etc. We could also automatically give the selection box the color of the tag assigned to it, to make reading faster, or display the color tag in a corner.
Of course, I do not know how much you would like to develop Tropy in the direction of an analysis software (and therefore no longer only a collection software), but one could very well imagine researchers who would manually tag their corpus to then count occurrences or co-occurrences. It could be very useful on small to medium corpora on which the OCR is not possible.
In short, I do not know if all these ideas deserve an answer today, but they are things that would make Tropy’s use justifiable in my case.