Pointing at Objects: Is vs. Was

Hello,

If I were pointing at something or someone on a picture, which of the following is correct?

A. This is my mom.
B. This was my mom.


1. Is 'is' correct because I'm simply telling someone the fact that the person on the picture is my mom?
2. Or 'is' is correct simply because I'm currently pointing at my mom on the picture?

3. Or should I use 'was' because the picture was surely taken in the past?
4. What is the basis for using 'is' or 'was' in the example? Is it the time of pointing at something at the time of speaking or the time when the picture was taken?

C. This is my mom when she was 16.

D. This was my mom when she was 16.

5. Again, pointing at someone on a picture in the preceding example above, which is correct? And why?
6. Can I use 'that' instead of 'this' in this example even if I were holding a picture and talking to someone right next to me? Because my mom was probably far away from someone in front on the picture? Or it was the person next to me that was holding the picture so can I use 'that'?

E. That mold marking on the wall is because of the cold weather last December.
F. That mold marking on the wall was because of the cold weather last December.

7. Pointing at the mold marking on the wall, can I use 'is' because I'm pointing at the marking presently on the wall?
8. Or can I use 'is' because I'm currently pointing at the marking at the time of speaking?

9. Or should I use 'was' because the mold appeared on the wall during the cold weather last December and left a marking?
10. Again, what is the basis for using 'is' and 'was'? Is it the time of pointing at something at the time of speaking? Or the time when a marking is present on the wall? Or time when a mold appeared and left a marking?

I would very much appreciate your answers on each question. Thanks so much in advance.