This many vs these many

Question

I sent few pics to someone and she asked me "why so many pics". When I responded with "I always take this many pics", she told me that there is something wrong with the sentence.

As per other forums, "this many" works when talking about specific number. But I don't see any example of the same. If I have specific number, then use of "many" is not even justified.

Is there something I am missing about the use of "this many". If I were to use "this many" in above conversation, what modification will be needed to fix this?

Edit:

More context. I have a rule of sending pictures from one specific place every time. Since I normally take pics while in the cab, they get blurry. So, I take multiple and send the best one across. This time, I sent all the pictures instead. Hence the question on her part. I just want to mention to her that this 3-4 pictures thing is usual. In that case, I am unsure if "this many" is correct. It is just something, no one I know can satisfactorily answer, hence this post.

Answer 1

The difference between "These many pictures" and "This many pictures" could be referring more to what the speaker wants the qualifying word to apply to - either the many or the pictures.

So "I always take these many pictures" begins to sound like you always take those exact pictures (like the same pictures over and over) which happen to be "many".

Whereas "I always take this many pictures refers to the amount being the same whenever you take pictures (many). "This many" is referring to a singular noun many. You could say it to refer to the "many" pictures that you took on your own phone.

"That many" (as Jim commented) is similar (referring to a many as well, but on your friend's phone for instance).

See: https://english.stackexchange.com/questions/4325/using-that-and-this-interchangeably
e.g. - This phone right here. vs That phone over there.

Answer 2

This many pictures (This large amount of pictures, This small amount of pictures). These many pictures (These 8 pictures, These 9 pictures)

Answer 3

From pag 419 of Mastering English An Advanced Grammar for Non-native and Native Speakers:

Elsewhere, demonstratives normally serve as determiners (as in that exact moment, this way, etc.). BUT in connection with adjectives and quantifiers such as much and many, the singular demonstratives may serve also as degree adverbs, indicating a precise amount or measure:

(14) I didn't give her that much.

(15) Do we need this many recommendations?

(16) The worm was this long.

Yet, despite the number of stars in the sky being uncountable by nature, so no precise amount at all, the sentence I've never seen this many stars (in the sky) is uttered by the character "Ian" in an informal context in the last chapter of the fifth season of Shameless, "Love Songs (In the Key of Gallagher)"